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    2023 Vol. 22 No. 12 Previous Issue   

    Special Focus: Accelerating Rural Transformation in Asian Developing Countries
    Crop Science
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    Special Focus: Accelerating Rural Transformation in Asian Developing Countries
    Editorial-Accelerating rural transformation in Asian developing countries
    HUANG Ji-kun, Dong WANG, Christopher FINDLAY, Chunlai CHEN
    2023, 22(12): 3565-3567.  DOI: 10.1016/j.jia.2023.11.027
    Abstract ( )   PDF in ScienceDirect  

    All developing countries experience a process of rural transformation (RT), and the evidence available to date says that economies that transform their rural sectors more rapidly achieve faster growth and are also more inclusive.  However, not all countries are successful.  This special focus contains five papers related to the nature of rural transformation, its components, and consequences.1

    All authors respond to the proposition that understanding the nature and impact of RT is essential for policymakers, because of their role in its success.  A theme of the collection is the regional diversity in the experience of rural transformation and the value of the design of region-specific policies.

    Wang et al. (2023) provide a comprehensive analysis of the concept of RT, its measurement, and the various indicators used in related studies.  They adopt a definition of RT that is more extensive than the simple transformation of agriculture but also retains a focus on the rural economy (and, therefore, is a subset of the structural transformation of the whole economy).  They refer to the text of the definition by IFAD (2016, p. 23) as involving ‘rising agricultural productivity, commercialisation and diversification of production patterns and livelihoods,’ which also involves expanded off-farm employment.   The process also has consequences for inclusion and sustainability.

    A feature of RT is the greater use of markets for outputs such as high-value crops and inputs such as labour.  The development of markets in complementary services, such as transport and storage, also supports the use of output markets.  The authors note that RT involves significant changes in rural areas, including shifts in farming practices, land use, population movements, and interactions between primary and other sectors.   

    Given all its dimensions, the measurement of RT is a challenge. Current methods and indicators are often insufficient for policy decision-making due to a lack of objectivity, feasibility, accountability, comprehensiveness, and comparability. This study reviews various indicators, such as those referring to components including labour productivity, commercialisation, diversification, inclusiveness, and sustainability. The authors argue that future research could develop more effective measures to assess RT, especially in developing countries, and they review a range of options for further attention.

    Shi and Huang (2023) examine the dynamic relationship between RT and its consequences.  They concentrate on its impacts on income growth, and poverty reduction across different regions in China over the past 40 years. The study uses provincial-level data to form indicators of RT.  Specifically, they assess how shifts from traditional agriculture to high-value agriculture (RT1) and the rise of non-farm employment (RT2) have impacted rural income and poverty.  These indicators are commonly used in papers in the research project from which this collection is drawn.

    The study finds: 1) a positive correlation between both aspects of RT and per capita rural income. While both RT1 and RT2 have resulted in a significant increase in rural income, RT1’s impacts occur more in the later stage than early stage of RT, and RT2’s impacts happen in every stage of RT.  2) RT1 and RT2 have significantly contributed to the reduction of rural poverty.  The effect of RT1 is more dominant in the early stages of RT, while RT2 becomes more influential in later stages.  3) The level and speed of RT, along with its effects on income and poverty, vary considerably across regions. Eastern provinces, which are more economically developed, show higher levels of RT and better outcomes in terms of income growth and poverty reduction than other regions.

    The findings suggest the importance of targeted policies that promote high-value agriculture and expand rural non-farm employment according to the stage of transformation. And the paper also emphasizes the value of region-specific strategies and policies.

    Sudaryanto et al. (2023) explore the impact of RT on household income and poverty in Indonesia over the last 20 years.

    They report that RT in Indonesia has been characterized by rapid agricultural growth, particularly in the production of horticulture, estate crops, and livestock, which has surpassed the growth in grain production.  This shift reflects farmers’ orientation from subsistence to market-driven production.  Additionally, there has been an increasing engagement of rural laborers in non-farm employment, contributing to the diversification of rural economies.

    Then, using data from 34 provinces in Indonesia from 2000 to 2020, they find growth in both RT1 and RT2, with each also positively associated with the growth of rural household income and a decrease in poverty rates. However, they find that the speed of this structural transformation and its consequences varies across regions.

    However, there are regional disparities: Regions with a higher level of RT, like those centred around major cities such as Medan and Jakarta, show a more significant increase in household income and a more pronounced reduction in poverty. In contrast, less developed regions, especially those in Eastern Indonesia, face more significant challenges in reducing poverty.  

    Policies aimed at improving rural income and reducing poverty should integrate, the authors of the Indonesia paper argue, approaches promoting high-value agriculture and expanding rural non-farm employment, but also pay special attention to regional situations and adopt a contextual policy framework that considers regional diversification in natural resources endowments as well as socio-cultural aspects.

    Abedullah et al. (2023) explore the role of RT in enhancing rural per capita income and reducing poverty in Pakistan from 1981 to 2019.  The research uses district-level data to measure RT1 and RT2.  The authors find that: 1) Both RT1 and RT2 positively affect rural per capita income, with RT1 having a more pronounced impact than RT2 (as in the case of China).  2) Both RT1 and RT2 are effective in reducing rural poverty, but RT2 becomes more in the later stages of rural development (as also the case in China).  3) Significant regional disparities occur in the process and impact of RT. Districts at advanced stages of RT positively correlate with increased income and reduced poverty rate (as was also found in both China and Indonesia).

    We noted RT’s contribution to inclusion generally, but another important element of the work completed to date is attention to RT’s gender inclusiveness.  Rola-Rubzen et al. (2023) systematically review 84 studies from 1960 to 2021 to understand how RT affects gender indicators and how gender inclusiveness influences RT.

    RT significantly impacts women’s work, income, empowerment, wellbeing, and time allocation. It leads to positive outcomes for women, such as increased employment and empowerment opportunities, but also introduces challenges, including unstable income sources and increased workloads.

    Due to RT, women are working more, including greater involvement in both on-farm labour and off-farm or non-agricultural employment. While this shift can improve women’s livelihoods, it also results in complexities such as wage discrimination and job insecurity.

    The stability of the additional income associated with RT is questionable. Shifts towards high-value agricultural commodities, for example, contribute to reduced income stability. Moreover, women’s increased income does not always equate to increased control over household financial resources.

    RT can enhance women’s empowerment, mainly through increased educational opportunities for girls and improved income. Nevertheless, shifts to high-value agriculture sometimes reduce women’s control over income and resources, indicating a complex interplay between RT and empowerment.

    In summary, these papers find a positive association of the indicators of rural transformation (high-value products and off-farm employment) with rural income growth and poverty reduction, but with differential impacts at different stages of development.  All studies also finds significant regional variation in performance.

    These studies recommends targeted policies to enhance high-value agriculture and expand rural non-farm employment but with region-specific strategies.  The research also highlights the challenges in implementing effective RT strategies, such as land distribution inequalities, credit market limitations, and access to modern agricultural techniques.

    The work has led to discussion of policy options that might accelerate rural transformation.  The next step is to systematically consider the drivers of the changes in rural transformation indicators.  The framework applied in the project from which these papers are drawn pays attention to institutions, policies, and investments (IPIs).  Each component of the IPIs is likely to contribute to both RT1 and RT2 to varying degrees.  The study of the association of elements of the IPIs with the indicator and, thereby, the outcomes of RT is a topic of current research.  However, some work on the relevant components of the IPIs has been published for the case of China (Huang 2022), which provides direction for this research.  

    Relevant institutions, for example, include the conditions of access to land (the development of land markets, in other words) and markets for water and labour.  Markets that support the application of mechanisation are also expected to be essential, as will other markets for complementary services.  Various policies will also influence the emergence of new markets (Barrett et al. 2022).  

    Other relevant policies include those affecting incentives faced by rural households, including price regulation, trade policy management, and applying taxes and subsidies.  Sometimes, these linkages also operate in both directions (from policy to RT and back again): an example is trends in trade policy (Anderson 2023) and foreign direct investment (Hu et al. 2023).

    Examples of investments include those related to infrastructure (such as roads or irrigation) and technology (through systems of research and development applied to agriculture). As noted, these are topics for further work, intending to map the priorities among the IPIs for accelerating RT depending on its current stage and regional context.  

    While RT generally leads to positive outcomes for women, it also presents risks and challenges.  Future RT policies and programs should be more gender-inclusive to maximize benefits for women and further RT itself.  These are critical elements of the larger package of IPIs. 

    A review of rural transformation studies: Definition, measurement, and indicators
    Dong WANG, Chunlai CHEN, Christopher FINDLAY
    2023, 22(12): 3568-3581.  DOI: 10.1016/j.jia.2023.10.038
    Abstract ( )   PDF in ScienceDirect  
    The paper reviews studies of rural transformation in three dimensions - definition, measurement, and indicators - and summarises the findings of rural transformation research. The scope of rural transformation includes four elements - productivity, rurality, inclusiveness, and sustainability. Current concepts of the dimensions of rural transformation and their associated indicators are insufficient for policy decision-making, as they lack objectivity, feasibility, accountability, comprehensiveness, and comparability. Future research to develop new measures to assess rural transformation in developing countries is valuable. Furthermore, there is potential to explore the topic in some directions: urbanisation strategy, public intervention (i.e., institution, policy, and investment), gender inclusiveness, market creation, and international trade.
    Rural transformation, income growth, and poverty reduction by region in China in the past four decades
    SHI Peng-fei, HUANG Ji-kun
    2023, 22(12): 3582-3595.  DOI: 10.1016/j.jia.2023.10.037
    Abstract ( )   PDF in ScienceDirect  

    China has experienced rapid rural transformation in the past four decades.  Accompanying the rapid transformation is a significant rise in rural household income and a substantial fall in rural poverty.  This paper examines the evolutions of and the relationships between rural transformation (high-value agriculture and rural non-farm employment) and its outcomes (per capita rural income and rural poverty incidence) using provincial-level ata.  The results show that 31 provinces/autonomous regions/municipalities have undergone significant rural transformation, but the level and speed of rural transformation differed considerably.  Moreover, an increased level of rural transformation is often associated with higher per capita rural income and reduced rural poverty incidence.  Notably, a category of provincial rural transformation based on high-value agriculture and rural non-farm employment is also analyzed.  We further discuss the likely impacts of institutions, policies, and investments (IPIs) on rural transformation and conclude with policy implications.

    Regional rural transformation and its association with household income and poverty incidence in Indonesia in the last two decades
    Tahlim SUDARYANTO, ERWIDODO, Saktyanu Kristyantoadi DERMOREDJO, Helena Juliani PURBA, Rika Reviza RACHMAWATI, Aldho Riski IRAWAN
    2023, 22(12): 3596-3609.  DOI: 10.1016/j.jia.2023.11.029
    Abstract ( )   PDF in ScienceDirect  
    Increasing rural household income and reducing poverty rank among Indonesia’s top development priorities. Promoting rural transformation is one strategic policy framework to achieve these goals. In the last three decades, agricultural production has shifted from low-value food crops to high-value commodities, such as horticulture, estate crops, and livestock. Previous studies have analyzed rural transformation in Indonesia at the national level, but information on the magnitudes of impact across regions remains scarce. This study aims to analyze the changes in rural transformation at a regional level in the past two decades. The research utilizes secondary data from Statistics Indonesia (BPS), covering 34 provinces from 2000 to 2020, analyzed using descriptive and panel data regression analyses. The results show an increasing trend in the share of high-value agriculture (RT1) and rural non-farm employment (RT2). Both RT1 and RT2 are positively associated with the growth of rural household income and a lower poverty rate. However, the speed of structural transformation (ST), RT1, RT2, rural income growth, and poverty reduction vary across regions. This research implies that improving rural income and reducing poverty should be done by integrating policies, i.e., promoting highvalue agriculture and expanding rural non-farm employment. Particular attention should also be given to provinces with slow growth in ST, RT1, RT2, and rural household income.
    Developing strategy for rural transformation to alleviate poverty in Pakistan: Stylized facts from panel analysis
    ABEDULLAH, Shujaat FAROOQ, Farah NAZ
    2023, 22(12): 3610-3623.  DOI: 10.1016/j.jia.2023.11.028
    Abstract ( )   PDF in ScienceDirect  
    Sustainable income growth and poverty reduction remain critical challenges at the forefront of research in Pakistan, particularly in rural areas. To overcome these challenges, the role of rural transformation (RT) has emerged and gained importance in recent years. The present study is based on district-level data and covers the period from 1981 to 2019. The study attempts to quantify the role of rural transformation in boosting rural per capita income and alleviating rural poverty in the country. The study also aims to explore the impact of stages of rural transformation on rural per capita income and rural poverty alleviation. The empirical findings reveal that rural transformation (RT1 and RT2) is essential in enhancing rural per capita income and alleviating rural poverty. The role of the share of high-value crops (RT1) is more pronounced than the share of non-farm employment (RT2) in boosting rural per capita income and poverty alleviation. The trend of larger contribution of RT1 to enhance rural per capita income also continued at 2nd stage of rural transformation. In the case of poverty reduction, at 3rd stage of rural transformation, the role of RT2 is dominant. Our results indicate that districts at higher stages of rural transformation (both RT1 and RT2) tend to correlate positively with increased rural per capita income and reduced poverty rates, suggesting that progress in rural transformation is associated with improved economic conditions. However, it is important to note that this correlation does not necessarily imply a direct causal relationship between rural transformation and these economic outcomes; other factors may have influenced this relationship. In addition, the welfare impacts are more noticeable among the districts where a simultaneous shift from grain crops to cash crops and from farm employment to non-farm employment is observed. The study provides baseline information to learn experiences from fast-growing districts and to replicate the strategies in other districts, which boosts the RT process that may increase rural per capita income and enhance poverty reduction efforts.
    Gender and rural transformation: A systematic literature review
    Maria Fay ROLA-RUBZEN, Hue T. VUONG, Claire DOLL, Curtis ROLLINS, Jon Marx SARMIENTO, Mohammad Jahangir ALAM, Ismat Ara BEGUM
    2023, 22(12): 3624-3637.  DOI: 10.1016/j.jia.2023.10.035
    Abstract ( )   PDF in ScienceDirect  
    Rural transformation can improve poverty reduction, living standards, and health outcomes in developing countries. However, impacts associated with rural transformation vary by region, household, and individual trait (including gender). While research on rural transformation has been increasing over the last decade, there has been no comprehensive review conducted on the relationships between gender and rural transformation. Here, we conduct a systematic literature review to investigate the impacts of rural transformation on gender and the influence of gender inclusiveness on rural transformation. We reviewed 82 studies from 1960–2021 that explore the relationships between rural transformation and gender. We then developed a framework that captures incidences and flow directions between indicators. Results show that most studies examined the impacts of rural transformation on women and between gender indicators. Few investigated the role of women and the influence of gender inclusiveness on rural transformation. Overall, studies showed that rural transformation typically leads to positive outcomes for women regarding employment, income, and empowerment. However, negative impacts on women’s control over income, stability of new income sources, and access to healthy food are also common. Tailoring future development policies and programs to explicitly account for gender inclusiveness can lead to more successful rural transformation.
    Crop Science
    Phosphorylation of SiRAV1 at Ser31 regulates the SiCAT expression to enhance salt tolerance in Setaria italica
    LI Qiao-lu, LI Zhi-yong, WANG Meng-meng, YAN Jing-wei, FANG Lin
    2023, 22(12): 3638-3651.  DOI: 10.1016/j.jia.2023.04.034
    Abstract ( )   PDF in ScienceDirect  
    Salinity severely affects plant growth and development. Thus, it is crucial to identify the genes functioning in salt stress response and unravel the mechanism by which plants against salt stress. This study used the phosphoproteomic assay and found that 123 of the 4 000 quantitative analyzed phosphopeptides were induced by salt stress. The functional annotation of the non-redundant protein database (NR) showed 23 differentially expressed transcription factors, including a phosphopeptide covering the Serine 31 in the RAV (related to ABI3/VP1) transcription factor (named SiRAV1). SiRAV1 was located in the nucleus. Phenotypic and physiological analysis showed that overexpressing SiRAV1 in foxtail millet enhanced salt tolerance and alleviated the salt-induced increases of H2O2 accumulation, malondialdehyde (MDA) content, and percent of electrolyte leakage. Further analysis showed that SiRAV1 positively regulated SiCAT expression to modulate the catalase (CAT) activity by directly binding to the SiCAT promoter in vivo and in vitro. Moreover, we found that phosphorylation of SiRAV1 at the Ser31 site positively regulated salt tolerance in foxtail millet via enhancing its binding ability to SiCAT promoter but did not affect its subcellular localization. Overall, our results define a mechanism for SiRAV1 function in salt response where salt-triggered phosphorylation of SiRAV1 at Ser31 enhances its binding ability to SiCAT promoter, and the increased SiCAT expression contributes to salt tolerance in foxtail millet.
    Growth of tandem long-mat rice seedlings using controlled release fertilizers: Mechanical transplantation can be more economical and high yielding
    HE Wen-jun, HE Bin, WU Bo-yang, WANG Yu-hui, YAN Fei-yu, DING Yan-feng, LI Gang-hua
    2023, 22(12): 3652-3666.  DOI: 10.1016/j.jia.2023.05.007
    Abstract ( )   PDF in ScienceDirect  
    The traditional soil-based rice seedling production methods for mechanical transplanting are resource-intensive, time consuming and laborious. The improvement and optimization of nutrient management in soil-less nursery raising methods like tandem long-mat seedlings (TLMS) are necessary for the resource-efficient cultivation of rice. In the present study, a controlled-release fertilizer (CRF)-polymer-coated compound fertilizer with 3 months release period (PCCF-3M) was applied as seedling fertilizer (SF), and five different dosages of SF (SF-0, SF-10, SF-20, SF-30, and SF-40) were compared with an organic substrate as the control (CK). Among all SF treatments, the best results were obtained with the application of 20 g/tray of SF (SF-20), as the seedling quality and machine transplanting quality were comparable to those of CK. In contrast, the lower dosages (SF-0 and SF-10) resulted in low nitrogen content and reduced shoot growth, while the higher dosages (SF-30 and SF-40) resulted in toxicity (increased malondialdehyde accumulation) and inhibited the root growth. Similarly, SF-20 increased panicle number (5.6–7.0%) and yield (4.3–5.3%) compared with CK, which might be related to the remaining SF entangled in the roots supporting the tiller growth of rice seedlings in the field. Moreover, SF-20 reduced the seedling block weight (53.1%) and cost of seedling production (23.5%) but increased the gross margin, indicating that it was easy to handle and economical. Taken together, our results indicate that SF-20 is a cost-effective way to promote the growth and transplanting efficiency of rice seedlings. To our knowledge, this study is the first to determine the optimum dosage of CRF for the soil-less production of rice seedlings.
    Twice-split phosphorus application alleviates low-temperature impacts on wheat by improved spikelet development and setting
    XU Hui, HOU Kuo-yang, FANG Hao, LIU Qian-qian, WU Qiu, LIN Fei-fei, DENG Rui, ZHANG Lin-jie, CHEN Xiang, LI Jin-cai
    2023, 22(12): 3667-3680.  DOI: 10.1016/j.jia.2023.09.013
    Abstract ( )   PDF in ScienceDirect  
    Extreme low-temperature incidents have become more frequent and severe as climate change intensifies.  In Huang-Huai-Hai wheat growing area of China, the late spring coldness occurring at the jointing-booting stage (the anther interval stage) has resulted in significant yield losses of winter wheat.  This study attempts to develop an economical, feasible, and efficient cultivation technique for improving the low-temperature (LT) resistance of wheat by exploring the effects of twice-split phosphorus application (TSPA) on wheat antioxidant characteristics and carbon and nitrogen metabolism physiology under LT treatment at the anther interval stage using Yannong 19 as the experimental material.  The treatments consisted of traditional phosphorus application and TSPA, followed by a –4°C LT treatment and natural temperature (NT) control at the anther interval stage.  Our analyses showed that, compared with the traditional application, the TSPA increased the net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) of leaves and reduced the intercellular carbon dioxide concentration (Ci).  The activity of carbon and nitrogen metabolism enzymes in the young wheat spikes was also increased by the TSPA, which promoted the accumulation of soluble sugar (SS), sucrose (SUC), soluble protein (SP), and proline (Pro) in young wheat spike and reduced the toxicity of malondialdehyde (MDA).  Due to the improved organic nutrition for reproductive development, the young wheat spikes exhibited enhanced LT resistance, which reduced the sterile spikelet number (SSN) per spike by 11.8% and increased the spikelet setting rate (SSR) and final yield by 6.0 and 8.4%, respectively, compared to the traditional application.  The positive effects of split phosphorus application became more pronounced when the LT treatment was prolonged.  
    Plant Protection
    Resistance risk and molecular mechanism associated with resistance to picoxystrobin in Colletotrichum truncatum and Colletotrichum gloeosporioides
    SHI Niu-niu, LIAN Jin-pan, QIU De-zhu, CHEN Fu-ru, DU Yi-xin
    2023, 22(12): 3681-3693.  DOI: 10.1016/j.jia.2023.07.037
    Abstract ( )   PDF in ScienceDirect  

    Anthracnose, caused by Colletotrichum truncatum and Cgloeosporioides, is amongst the most serious diseases of soybean in China.  Picoxystrobin, a quinone outside inhibitor fungicide, is commonly used for the control of anthracnose.  Its resistance risk and mechanism in Ctruncatum and Cgloeosporioides are unclear.  In this study, the sensitivities of 128 Ctruncatum and 121 Cgloeosporioides isolates to picoxystrobin were investigated, and unimodal distributions were observed with average EC50 values of 0.7740 and 1.1561 μg mL–1, respectively.  Eleven picoxystrobin-resistant mutants of Ctruncatum and six mutants of Cgloeosporioides were acquired, with EC50 values varying from 5.40–152.96 and 13.53–28.30 μg mL–1, respectively.  Compared to the parental isolates, mutants showed similar or higher relative fitness in conidial production and germination, and pathogenicity.  Collectively, the resistance risk of Ctruncatum and Cgloeosporioides to picoxystrobin is moderate to high.  There was positive cross-resistance between picoxystrobin and pyraclostrobin, but not between picoxystrobin and fluazinam, difenoconazole, or propiconazole.  The G143S mutation in Cyt b protein was detected in seven high-resistant mutants of Ctruncatum (RF>100), and G137R occurred in four moderate-resistant mutants (RF<50).  Contrastingly, there were no point mutations in Cyt b of any Cgloeosporioides mutants.  Molecular docking confirmed that two mutations conferred different resistance levels to picoxystrobin.  Under greenhouse trials, picoxystrobin did not control mutants with the G143S mutation, those bearing G137R or no point mutation were somewhat controlled, but at a lower level compared to wild-type isolates.  These results showed that integrated management strategies should be implemented to preserve fungicide effectiveness.

    Physiological and biochemical characteristics of boscalid resistant isolates of Sclerotinia sclerotiorum from asparagus lettuce
    SHI Dong-ya, LI Feng-jie, ZHANG Zhi-hui, XU Qiao-nan, CAO Ying-ying, Jane Ifunanya MBADIANYA, LI Xin, WANG Jin, CHEN Chang-jun
    2023, 22(12): 3694-3708.  DOI: 10.1016/j.jia.2023.09.024
    Abstract ( )   PDF in ScienceDirect  

    Laboratory mutants of Sclerotinia sclerotiorum (Lib) de Bary, resistant to boscalid, have been extensively characterized.  However, the resistance situation in the lettuce field remains largely elusive.  In this study, among the 172 Ssclerotiorum isolates collected from asparagus lettuce field in Jiangsu Province, China, 132 isolates (76.74%) exhibited low-level resistance to boscalid (BosLR), with a discriminatory dose of 5 μg mL–1.  In comparison to the boscalid-sensitive (BosS) isolates, most BosLR isolates demonstrated a slightly superior biological fitness, as evidenced by data on mycelial growth, sclerotium production and pathogenicity.  Moreover, most BosLR isolates showed comparable levels of oxalic acid (OA) accumulation, increased exopolysaccharide (EPS) content and reduced membrane permeability when compared to the BosS isolates.  Nevertheless, their responses to distinct stress factors diverged significantly.  Furthermore, the effectiveness of boscalid in controlling BosLR isolates on radish was diminished compared to its efficacy on BosS isolates.  Genetic mutations were identified in the SDH genes of BosLR isolates, revealing the existence of three resistant genotypes: I (A11V at SDHB, SDHBA11V), II (Q38R at SDHC, SDHCQ38R) and III (SDHBA11V+SDHCQ38R).  Importantly, no cross-resistance was observed between boscalid and other fungicides such as thifluzamide, pydiflumetofen, fluazinam, or tebuconazole.  Our molecular docking analysis indicated that the docking total score (DTS) of the type I resistant isolates (1.3993) was lower than that of the sensitive isolates (1.7499), implying a reduced affinity between SDHB and boscalid as a potential mechanism underlying the boscalid resistance in Ssclerotiorum.  These findings contribute to an enhanced comprehension of boscalid’s mode of action and furnish valuable insights into the management of boscalid resistance.

    Seedling Petri-dish inoculation method: A robust, easy-to-use and reliable assay for studying plant–Ralstonia solanacearum interactions
    CAO Peng, CHEN Jia-lan, LI Ning-ning, ZHANG Shuang-xi, WANG Rong-bo, LI Ben-jin, LIU Pei-qing, AN Yu-yan, ZHANG Mei-xiang
    2023, 22(12): 3709-3719.  DOI: 10.1016/j.jia.2023.05.020
    Abstract ( )   PDF in ScienceDirect  

    Ralstonia solanacearum causes a lethal bacterial wilt disease in many crops, leading to huge losses in crop production every year.  Understanding of plant–Rsolanacearum interactions will aid to develop efficient strategies to control the disease.  As a soilborne pathogen, Rsolanacearum naturally infects plants via roots.  A huge limitation in studying plant–Rsolanacearum interactions is the large variation of Rsolanacearum infection assay due to the variable soil conditions and uneven inoculum exposure.  Here, we developed a robust and reliable Petri-dish inoculation method which allows consistent and stable infection in young plant seedlings.  This method is easy to use, takes about only 10 days from seed germination to the completion of inoculation assay, and requires less inoculum of bacteria as well as growth chamber space.  We proved the efficacy of the seedling Petri-dish inoculation method by analyzing plant defense primed by molecular patterns, resistance of defense-related plant mutants, and virulence of Rsolanacearum mutants.  Furthermore, we demonstrated that the seedling Petri-dish inoculation method can be applied to other host plants such as tobacco and has great potential for high-throughput screening of resistant plant germplasms to bacterial wilt in the future.

    Serine protease inhibitors LmSPN2 and LmSPN3 co-regulate embryonic diapause in Locusta migratoria manilensis (Meyen) via the Toll pathway
    FENG Shi-qian, ZHANG Neng, CHEN Jun, ZHANG Dao-gang, ZHU Kai-hui, CAI Ni, TU Xiong-bing, ZHANG Ze-hua
    2023, 22(12): 3720-3730.  DOI: 10.1016/j.jia.2023.05.019
    Abstract ( )   PDF in ScienceDirect  

    Female adults of the migratory locust, Locusta migratoria manilensis (Meyen), can sense seasonal photoperiod changes, which induces embryonic diapause as a key strategy to overwinter.  Serine protease inhibitor genes (SPNs) were thought to play key roles during diapause, while few SPNs were functionally characterized.  LmSPN2 was one of those genes differentially expressed between diapause and non-diapause eggs; however, its biological function remained to be explored.  So, we conducted RNAi knockdown of LmSPN2, resulting in a significant decrease of the egg diapause rate by 29.7%.  Using yeast two-hybrid assays, co-immunoprecipitation, and pull-down methods, we found an interaction between LmSPN2 and LmSPN3, which was proved to be mediated by a glutamate (E331) binding site of LmSPN2.  RNAi knockdown of LmSPN3 resulted in a significant increase in diapause rate by 14.6%, indicating an inverse function of LmSPN2 and LmSPN3 on diapause regulation.  Double knockdown of two SPN genes resulted in a 26.4% reduction in diapause rate, indicating that LmSPN2 was the dominant regulatory signal.  Moreover, we found four Toll pathway genes (easter, spätzle, pelle, and dorsal) upregulated significantly after the knockdown of LmSPN2 while downregulated after the knockdown of LmSPN3.  Therefore, we speculate that two SPNs regulate diapause through the Toll pathway.  Our results indicated that LmSPN2 positively regulates locust egg entry into diapause, while LmSPN3 is a negative regulator of embryonic commitment to diapause.  Their interaction is mediated by the binding site of E331 and influences egg diapause through the Toll pathway.  This mechanistic understanding of diapause regulation expands our understanding of insect developmental regulation and provides functional targets for developing locust management strategies.

    Thelytokous Diglyphus wani: A more promising biological control agent against agromyzid leafminers than its arrhenotokous counterpart
    DU Su-jie, YE Fu-yu, XU Shi-yun, WAN Wei-jie, GUO Jian-yang, YANG Nian-wan, LIU Wan-xue
    2023, 22(12): 3731-3743.  DOI: 10.1016/j.jia.2023.06.002
    Abstract ( )   PDF in ScienceDirect  

    Diglyphus wani (Hymenoptera: Eulophidae) is a dominant parasitoid that attacks agromyzid leafminers.  Two reproductive types occur in Dwani: arrhenotoky (in which virgin females produce only male offspring; and virgin females mate with males to produce bisexual offspring) and thelytoky (in which virgin females produce female offspring).  As a potential biological control agent, exploring the differences in the relevant biological parameters of both strains is necessary.  In this study, comparisons between the two strains of Dwani were performed by evaluating the life table and host-killing rate.  The thelytokous strain exhibited significantly better life table parameters than its arrhenotokous counterpart.  Higher values for the intrinsic rate of increase, finite rate of increase, net reproductive rate, and fecundity were found in the thelytokous strain.  The thelytokous strain also performed better than the arrhenotokous strain in terms of net parasitism, host-feeding, host-stinging, and total host-killing rates.  Thus, populations of the thelytokous strain could grow fast and kill more hosts.  In conclusion, the thelytokous strain of Dwani may be the more promising biological agent against agromyzid leafminers compared to its arrhenotokous counterpart.  Also, since the thelytokous strain of Dwani is only known to produce females, it should be given priority in future biocontrol applications owing to the cost savings of breeding only females.

    Animal Science · Veterinary Medicine
    Transcriptome-based analysis of key genes and pathways affecting the linoleic acid content in chickens
    ZHAO Wen-juan, YUAN Xiao-ya, XIANG Hai, MA Zheng, CUI Huan-xian, LI Hua, ZHAO Gui-ping
    2023, 22(12): 3744-3754.  DOI: 10.1016/j.jia.2023.02.019
    Abstract ( )   PDF in ScienceDirect  

    Linoleic acid is an essential polyunsaturated fatty acid that cannot be synthesized by humans or animals themselves and can only be obtained externally.  The amount of linoleic acid present has an impact on the quality and flavour of meat and indirectly affects consumer preference.  However, the molecular mechanisms influencing the deposition of linoleic acid in organisms are not clear.  As the molecular mechanisms of linoleic acid deposition are not well understood, to investigate the main effector genes affecting the linoleic acid content, this study aimed to screen for hub genes in slow-type yellow-feathered chickens by transcriptome sequencing (RNA-Seq) and weighted gene coexpression network analysis (WGCNA).  We screened for candidate genes associated with the linoleic acid content in slow-type yellow-feathered broilers.  A total of 399 Tiannong partridge chickens were slaughtered at 126 days of age, fatty acid levels were measured in pectoral muscle, and pectoral muscle tissue was collected for transcriptome sequencing.  Transcriptome sequencing results were combined with phenotypes for WGCNA to screen for candidate genes.  KEGG enrichment analysis was also performed on the genes that were significantly enriched in the modules with the highest correlation.  A total of 13 310 genes were identified after quality control of transcriptomic data from 399 pectoral muscle tissues.  WGCNA was performed, and a total of 26 modules were obtained, eight of which were highly correlated with the linoleic acid content.  Four key genes, namely, MDH2, ATP5B, RPL7A and PDGFRA, were screened according to the criteria |GS|>0.2 and |MM|>0.8.  The functional enrichment results showed that the genes within the target modules were mainly enriched in metabolic pathways.  In this study, a large-sample-size transcriptome analysis revealed that metabolic pathways play an important role in the regulation of the linoleic acid content in Tiannong partridge chickens, and MDH2, ATP5B, RPL7A and PDGFRA were screened as important candidate genes affecting the linoleic acid content.  The results of this study provide a theoretical basis for selecting molecular markers and comprehensively understanding the molecular mechanism affecting the linoleic acid content in muscle, providing an important reference for the breeding of slow-type yellow-feathered broiler chickens.

    Characteristics of Mycobacterium tuberculosis serine protease Rv1043c in enzymology and pathogenicity in mice
    TANG Yang-yang, CUI Ying-ying, JIANG Yan-yan, SHAO Ming-zhu, ZANG Xin-xin, DANG Guang-hui, LIU Si-guo
    2023, 22(12): 3755-3768.  DOI: 10.1016/j.jia.2023.06.025
    Abstract ( )   PDF in ScienceDirect  

    The serine proteases of Mycobacteria tuberculosis (Mtb) are important contributors to the process of bacterial invasion and its pathogenesis.  In the present study, we systematically characterized the role of the Rv1043c protein in Mycobacterium infection by purifying the Rv1043c protein in Escherichia coli and constructing a Mycobacterium smegmatis (Msg) strain overexpressing Rv1043c (Msg_Rv1043c).  We found that Rv1043c had serine protease activity and localized to the surface of Mtb.  We determined that the optimal pH and temperature for the Rv1043c serine protease were 9.0 and 45°C, respectively.  Moreover, the serine protease activity of Rv1043c was enhanced by divalent metal ions of Ca2+ and Mg2+.  Site-directed mutagenesis studies demonstrated that the serine 279 residue in Rv1043c plays a catalytic role.  Additionally, mouse model studies confirmed that Rv1043c significantly enhanced the survival of Msg in vivo, induced pulmonary injury and lung cell apoptosis, and promoted the release of pro-inflammatory cytokines interleukin-1β and interleukin-6 in mice.  This study presents novel insights into the relationship between mycobacterial serine protease and the pathogenesis of the disease.

    Agro-ecosystem & Environment
    Identifying the critical phosphorus balance for optimizing phosphorus input and regulating soil phosphorus effectiveness in a typical winter wheat-summer maize rotation system in North China
    XU Meng-ze, WANG Yu-hong, NIE Cai-e, SONG Gui-pei, XIN Su-ning, LU Yan-li, BAI You-lu, ZHANG Yin-jie, WANG Lei
    2023, 22(12): 3769-3782.  DOI: 10.1016/j.jia.2023.05.030
    Abstract ( )   PDF in ScienceDirect  

    Phosphorus (P) is a nonrenewable resource and a critical element for plant growth that plays an important role in improving crop yield.  Excessive P fertilizer application is widespread in agricultural production, which not only wastes phosphate resources but also causes P accumulation and groundwater pollution.  Here, we hypothesized that the apparent P balance of a crop system could be used as an indicator for identifying the critical P input in order to obtain a high yield with high phosphorus use efficiency (PUE).  A 12-year field experiment with P fertilization rates of 0, 45, 90, 135, 180, and 225 kg P2O5 ha–1 was conducted to determine the crop yield, PUE, and soil Olsen-P value response to P balance, and to optimize the P input.  Annual yield stagnation occurred when the P fertilizer application exceeded a certain level, and high yield and PUE levels were achieved with annual P fertilizer application rates of 90–135 kg P2O5 ha–1.  A critical P balance range of 2.15–4.45 kg P ha–1 was recommended to achieve optimum yield with minimal environmental risk.  The critical P input range estimated from the P balance was 95.7–101 kg P2O5 ha–1, which improved relative yield (>90%) and PUE (90.0–94.9%).  In addition, the P input–output balance helps in assessing future changes in Olsen-P values, which increased by 4.07 mg kg–1 of P for every 100 kg of P surplus.  Overall, the P balance can be used as a critical indicator for P management in agriculture, providing a robust reference for limiting P excess and developing a more productive, efficient and environmentally friendly P fertilizer management strategy.

    Effects of residual plastic film on crop yield and soil fertility in a dryland farming system
    WANG Dong, XI Yue, SHI Xiao-yan, GUO Chao-li, ZHONG Yu-jie, SONG Chao, GUAN Yu, HUANG Lu, YANG Qi-feng, LI Feng-min
    2023, 22(12): 3783-3791.  DOI: 10.1016/j.jia.2023.04.026
    Abstract ( )   PDF in ScienceDirect  
    Plastic film mulch in agricultural production becomes essential to maintaining crop yields in arid and semiarid areas. However, the presence of residual film in farmland soil has also drawn much attention. In this study, three experiments were conducted. The first two experimental designs included 0, 450, 1 350, and 2 700 kg ha–1 of residual film pieces of approximately 5 cm side length added to field soil (0–20 cm soil depth) for seven years and added to pots for four years. In the third experiment, 1 350 kg ha–1 of the residual film with different side lengths (2–5, 5–10, 10–15, and 15–20 cm) was added to field soil for six years to explore the effect of residual film fragment size on soil nutrients, soil microorganisms, crop growth and yields. The residual film had little effect on the soil moisture at a field depth of 0–2 (or 0–1.8) m. There were no significant effects on organic carbon, total nitrogen, inorganic nitrogen, total phosphorus or available phosphorus in the 0–20 cm soil layer. The presence of residual film decreased the richness and diversity of the bacterial community of the surface soil of the residual film, but it had no significant effect on the microbial community of the non-surface soil. The emergence rates of wheat and lentils occasionally decreased significantly with different amounts of residue fragments added to the field. At 450–2 700 kg ha–1, the residual film reduced the plant height and stem diameter of maize and significantly reduced the shoot biomass of harvested maize by 11–19%. The average yields of maize and potato over the seven years decreased, but there were almost no significant statistical differences among the treatments. These results provide important data for a comprehensive scientific understanding of the effects of residual film on soil and crops in dryland farming systems.
    Derivation and validation of soil total and extractable cadmium criteria for safe vegetable production
    LI Li-jun, LI Kun, JIANG Bao, LI Ju-mei, MA Yi-bing
    2023, 22(12): 3792-3803.  DOI: 10.1016/j.jia.2023.05.008
    Abstract ( )   PDF in ScienceDirect  
    Determining the appropriate soil cadmium (Cd) criteria for vegetable production is important for ensuring that the Cd concentrations of the vegetables meet food safety standards. The soil extractable Cd criteria for vegetable production are also essential for both food safety and environmental management, especially in areas with a high natural background level. In the present study, soil total and extractable Cd criteria were derived using the approach of species sensitivity distribution integrated with soil aging and bioavailability as affected by soil properties. A dataset of 90 vegetable species planted in different soils was compiled by screening the published in literature in five bibliographic databases using designated search strings. The empirical soil–plant transfer model was applied to normalize the bioaccumulation data. After normalization, the intra-species variability was reduced by 18.3 to 84.4%. The soil Cd concentration that would protect 95% (HC5) of the species was estimated by species sensitivity distribution curves that were fitted by the Burr III function. The soil Cd criteria derived from the added approach for risk assessment were proposed as continuous criteria based on a combination of organic carbon and pH in the soil. Criteria for total Cd and EDTA-extractable Cd in the soil ranged from 0.23 to 0.61 mg kg–1 and from 0.09 to 0.25 mg kg–1, respectively. Field experimental data were used to validate the applicability and validity of these criteria. Most of the predicted HC5 values in the field experimental sites were below the 1:1 line. These results provide a scientific basis for soil Cd criteria for vegetable production that will ensure food safety.
    Short Communication
    Analyzing architectural diversity in maize plants using the skeletonimage- based method
    LIU Min-guo, Thomas CAMPBELL, LI Wei, WANG Xi-qing
    2023, 22(12): 3804-3809.  DOI: 10.1016/j.jia.2023.05.017
    Abstract ( )   PDF in ScienceDirect  
    Shoot architecture in maize is critical since it determines resource use, impacts wind and rain damage tolerance, and affects yield stability. Quantifying the diversity among inbred lines in heterosis breeding is essential, especially when describing germplasm resources. However, traditional geometric description methods oversimplify shoot architecture and ignore the plant’s overall architecture, making it difficult to reflect and illustrate diversity. This study presents a new method to describe maize shoot architecture and quantifies its diversity by combining computer vision algorithms and persistent homology. Our results reveal that persistent homology can capture key characteristics of shoot architecture in maize and other details often overlooked by traditional geometric analysis. Based on this method, the morphological diversity of shoot architecture can be mined (quantified), and the main shoot architecture types can be obtained. Consequently, this method can easily describe the diversity of shoot architecture in many maize materials.
    Biotechnology of α-linolenic acid in oilseed rape (Brassica napus) using FAD2 and FAD3 from chia (Salvia hispanica)
    XUE Yu-fei, INKABANGA TSEKE Alain, YIN Neng-wen, JIANG Jia-yi, ZHAO Yan-ping, LU Kun, LI Jia-na, DING Yan-song, ZHANG Shi-qing, CHAI You-rong
    2023, 22(12): 3810-3815.  DOI: 10.1016/j.jia.2023.05.018
    Abstract ( )   PDF in ScienceDirect  
    α-Linolenic acid (ALA, 18:3Δ9,12,15) is an essential fatty acid for humans since it is the precursor for the biosynthesis of omega-3 long-chain polyunsaturated fatty acids (LC-PUFA). Modern people generally suffer from deficiency of ALA because most staple food oils are low or lack ALA content. Biotechnological enrichment of ALA in staple oil crops is a promising strategy. Chia (Salvia hispanica) has the highest ALA content in its seed oil among known oil crops. In this study, the FAD2 and FAD3 genes from chia were engineered into a staple oil crop, oilseed rape (Brassica napus), via Agrobaterium tumefaciens-mediated transformation of their LP4-2A fusion gene construct driven by the seed-specific promoter PNapA. In seeds of T0, T1, and T2 lines, the average ALA contents were 20.86, 23.54, and 24.92%, respectively, which were 2.21, 2.68, and 3.03 folds of the non-transformed controls (9.42, 8.78, and 8.22%), respectively. The highest seed ALA levels of T0, T1, and T2 plants were 38.41, 35.98, and 39.19% respectively, which were 4.10–4.77 folds of the respective controls. FA-pathway enzyme genes (BnACCD, BnFATA, BnSAD, BnSCD, BnDGAT1, BnDGAT2, and BnDGAT3) and positive regulatory genes (BnWRI1, BnLEC1, BnL1L, BnLEC2, BnABI3, BnbZIP67, and BnMYB96) were all significantly up-regulated. In contrast, BnTT1, BnTT2, BnTT8, BnTT16, BnTTG1, and BnTTG2, encoding negative oil accumulation regulators but positive secondary metabolism regulators, were all significantly down-regulated. This means the foreign ShFAD2-ShFAD3 fusion gene, directly and indirectly, remodeled both positive and negative loci of the whole FA-related network in transgenic B. napus seeds.
    Letter
    Prevalence and genetic characterization of hepatitis E virus in Domestic Bactrian camels in Northern China: Identification of a novel HEV8 subtype
    LU Gang, YIN Xin, LIU Yan-qin, XIE Jin-xin, LI Shou-jun
    2023, 22(12): 3816-3820.  DOI: 10.1016/j.jia.2023.07.038
    Abstract ( )   PDF in ScienceDirect