All Cover Illustrations

    Volume 23, Issue 1, Jan. 2024

    Flower organ development in rice is closely related to yield, and its identity is mainly determined by A-, B-, C- and E-class genes, with the majority encoding MADS-box transcription factors. However, the regulatory mechanisms of these floral organ signature genes during flower development remains to be clarified. In this study, we successfully identified SPW2, which ecodes a plant-specific EMF1- like protein that involved in the H3K27me3 modification as an important component of the PRC2 complex. We demonstrated that SPW2 can mediate the process of H3K27me3 modification of pistil- related genesOsMADS3OsMADS13OsMADS58, and DLto regulate their expression in non- pistil organs of spikelets in rice, which expands our understanding of the molecular mechanism by which SPW2 regulates floral organ identity genes through epigenetic regulation. The cover photo illustrates the abnormal phenotypes of spw2, provided by professor Li Yunfeng’s research group from Key Laboratory of Application and Safety Control of Genetically Modified Crops, Academy of Agricultural Sciences, Southwest University, China.

    Volume 22, Issue 12, Dec. 2023

    Rural areas in Asian developing countries have undergone significant transformations in recent decades. This special focus aims to systematically review studies on rural transformation, shedding light on the trajectories and outcomes of this process across regions (such as provinces or districts) in China, Indonesia, and Pakistan. Empirical evidence reveals a consistent trend of transitioning agriculture from traditional to high-value practices and rural labor from farm-centric to non-farm activities over the past few decades. However, the pace of rural transformation varies considerably among countries and even within regions of a single country. Notably, accelerated rural transformation correlates with faster and more inclusive economic growth, ultimately contributing to poverty reduction. While rural transformation brings positive outcomes for women, including increased employment opportunities and empowerment, it also introduces challenges such as unstable income sources and heightened workloads. The articles delve into the probable impacts of rural institutions, policies, and investments (IPIs) on the pathways and consequences of rural transformation. Accompanying the special focus is a photo illustrating the various stages of rural transformation in Asia, contributed by Prof. Jikun Huang of Peking University and Prof. Abedullah Anjum of the Pakistan Institute of Development Economics. For further details, refer to pages 3565–3637.

    Volume 22, Issue 10, Oct. 2023

    The development of the kernel is closely related to the yield, mining essential genes for kernel development and analyzing molecular mechanisms serve as the foundation for achieving high-yield molecular breeding in maize. In this study, we successfully cloned Dek219 (Defective kernel219), a pivotal gene involved in maize kernel development, from a mutant with defective kernels. This gene encodes the DICER-LIKE1 protein, which is an essential enzyme in miRNA biogenesis. Furthermore, Dek219 is among the targets of selection during maize domestication, and natural variations in Dek219 are significantly associated with maize kernel length. We have also identified the excellent natural alleles and germplasm resources of Dek219, which provide important theoretical support and valuable gene resources for the cultivation of improved varieties of high-yield maize. The cover photo illustrates the process of breeding high-yield maize varieties with excellent allelic germplasm of Dek219, provided by Dr. Xie Sidi and Dr. Tian Ran from State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, China. See pages 2961–2980 for details.

    Volume 22, Issue 9, Sept. 2023

    Anhui Province is one of the regions with the most abundant resources of tea varieties in China, with its local varieties and ancient tea plants resources widely distributed and a long history of cultivation.  However, the large number of tea plant germplasm resources have not been collected, protected and utilized.  Therefore, the construction of core collection can not only improve the quality and efficiency of germplasm resources management, but also provide theoretical basis and core materials for the exploration of excellent gene resources.  In this study, genetic analysis on a large tea population consisting of 573 accessions including the ancient tea plants, landraces and cultivars in Anhui Province was performed using 60 SSR markers.  Moreover, a core collection contained 115 tea plant individuals was conducted, which conserved the whole genetic diversity but accounting for only 20% of the original germplasm resources.  The cover photo describes the tea plant germplasm resource bank, the phenotypes of three excellent varieties and an ancient tea plant, provided by the research team of Prof. Wei Chaoling from Anhui Agricultural University, China.  See pages 2719–2728 for details.

    Volume 22, Issue 8, Aug. 2023

    Schrankia costaestrigalis is a newly-reported potato pest in southern China.  The larvae damage potato tubers by feeding on tubers and foliage, either in the field or during storage.  The pest has caused great economic losses to farmers in the winter and early-spring potato planting areas.  Early-warning monitoring of this pest could protect domestic potato production.  Based on the environmental data (temperature and precipitation variables) and human influence index, the optimal species distribution model was used to estimate the potential geographical distribution in China under climate change.  Results showed that highly suitable habitats of S. ostaestrigalis were mainly located in Guangxi, Guangdong, Hong Kong, Fujian and Hainan.  The potential geographical distribution of S. ostaestrigalis in China will decrease under climate change, which shows a general tendency to move northeast and to the middle-high latitudes in the 2030s.  The agricultural practice of plastic film mulching in potato fields will provide a favorable microclimate for S. ostaestrigalis in the suitable areas.  More attention should be paid to the early warning and monitoring of S. ostaestrigalis in order to prevent its further spread in the China’s winter potato planting regions.  The cover photo depicts the developmental stages of S. ostaestrigalis, which is provided by Dr. Xian Xiaoqing and Ph D student Zhao Haoxiang from Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing.  See pages 2441–2455 for details.

    Volume 22, Issue 7, Jul. 2023

    Porcine reproductive and respiratory syndrome (PRRS) is a highly pathogenic infectious disease caused by PRRS virus (PRRSV). In our study, we reported the use of two precise CRISPR/Cas9 editing systems to identify important CD163 residues involved in PRRSV infection. From a dual-sgRNA editing system, we obtained the immortalized porcine alveolar macrophage (IPAM) cell lines with 40-residue (residues 523–562) deletion in CD163. From a CRISPR/Cas9-mediated HDR-based biallelic editing system, we generated precisely-edited cloned pigs with a single arginine (R) to alanine (A) substitution at position 561 of CD163 (CD163R561A), and PAMs were isolated from these CD163R561A pigs. PRRSV infection experiments showed that the IPAM cell line with the 40-residue deletion in CD163 were completely resistant to PRRSV-WUH3 (genotype 2 PRRSV) infection, and that CD163-R561A PAMs showed significantly lower susceptibility to PRRSV-WUH3 infection. Through this study, we believe that CD163 residues 523–562 are essential residues that mediate PRRSV infection, and that R561 is an important residue involved in PRRSV infection. Our study offers a valuable reference for exploring the mechanism of CD163-mediated PRRSV infection and provides other potential target sites for the generation of PRRSV-resistant CD163 gene-edited pigs. The cover photo depicts the CD163 specific edited pigs are resistant to PRRSV, which is provided by Dr. Xu Kui from Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing. See pages 2188–2199 for details.

    Volume 22, Issue 6, Jun. 2023

    High-molecular-weight glutenin subunits (HMW-GSs) are the most critical grain storage proteins that determine the unique processing qualities of wheat. Although it is a part of the superior HMW-GS pair (Dx5+Dy10), the contribution of the Dy10 subunit to wheat processing quality remains unclear. In this study, we elucidated the effect of Dy10 on wheat processing quality by generating and analyzing a deletion mutant (with the Dy10-null allele), and by elucidating the changes to wheat flour following the incorporation of purified Dy10. Based on an analysis of this mutant, we demonstrated that the Dy10 subunit is essential for maintaining dough strength. Furthermore, the Dy10-null allele positively affects the biscuit-making quality of wheat dough, making it potentially useful for soft wheat breeding programs. The cover photo depicts the formation process of wheat end-use quality, provided by the research team of Prof. Qi Pengfei and Dr. Wang Yan from Triticeae Research Institute, Sichuan Agricultural University, China. See pages 1609–1617 for details.

    Volume 22, Issue 5, May 2023

    Microwave treatment has been applied to flaxseed to achieve the efficient release of nutrients, inactivation of enzymes and improvement of flavor, etc.  However, it was still undefined how the techno-functionality of flaxseed protein changed upon microwave exposure.  We mainly elucidated how the antioxidant and interface properties changed for flaxseed protein based on the in-situ structural remodeling.  After microwave exposure, the storage protein was subjected to more compact assembly and subsequent permeation by membrane fragments of oil bodies in flaxseed.  Microwave exposure led to the retention of specific phenolic acids and promotion of antioxidant activities for flaxseed protein.  Improving oil–water interface activities of flaxseed protein produced the emulsion droplets with descending sizes and dense interface coating.  The current study could provide theoretical basis for tailoring the application functionality of protein fractions in flaxseed.  The photo depicts the potential changes in gas– and oil–water interface behavior of flaxseed protein after microwave exposure, provided by the research team of Dr. Deng Qianchun from Oil Crops Research Institute, Chinese Academy of Agricultural Sciences.  See pages 1574–1589 for details.  

    Volume 22, Issue 4, Apr. 2023

    Online automated identification of farmland pests is an important auxiliary means of pest control. In practical applications, the online insect identification system is often unable to locate and identify the target pest accurately due to factors such as small target size, high similarity between species and complex backgrounds. To facilitate the identification of insect larvae, a two-stage segmentation method, MRUNet, was proposed in this study. We conducted model training and comparative testing of MRUNet and previous methods on a semantic segmentation dataset of nine common farmland pest larvae. The experimental results show that the proposed two-stage image segmentation strategy is effective in dealing with small targets in complex backgrounds. This study provides a reliable reference for the automated identification of insect larvae. The cover photo shows the workflow of the proposed two-stage segmentation strategy and the structure of MRUNet, which is provided by Dr. Qiao Xi and Dr. Wang Fukuan from Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, China. See pages 1117–1130 for more details.

    Volume 22, Issue 3, Mar. 2023

    Arbuscular mycorrhizal fungi (AMF) help plants acquire phosphorus (P) from the soil. Cotton responds poorly to P-fertilizer application and lacks the ability to obtain P from sparingly soluble P sources, making it likely that cotton crucially depends on the AMF symbiosis. In this study, we addressed the role of mycorrhizal root traits and explored the interplay of root and mycorrhizal traits in enhancing P acquisition. We found that the more recent accessions had smaller root diameters, acquired less P, and produced less biomass at intermediate soil P levels, indicating an inadvertent varietal selection for thinner roots that provided less cortical space for AMF which then increased the need for a high P-fertilizer level. We conclude that selection for cotton should consider both morphological and mycorrhizal root traits when breeding for high-yielding cotton varieties. The photo depicts the carbon and P exchange between plants and AMF. The image was provided by MSc Ma Ruonan and Prof. Feng Gu from the College of Resources and Environmental Sciences, China Agricultural University, China. See pages 701–715 for details.

    Volume 22, Issue 2, Feb. 2023

    The melon fly Zeugodacus cucurbitae (Coquillett) is a very destructive tephritid pest across the world. Maleness-on-the-Y (MoY) is a primary factor that regulates sex determination in Ceratitis capitata and is supposed to be conserved in tephritid fruit flies. To investigate whether MoY plays a role in male sex determination of Z. cucurbitae, we examined the expression pattern of ZcMoY during embryogenesis and transiently inhibited ZcMoY in early embryos by RNAi. The expression pattern and knockdown phenotypes of ZcMoY indicate that ZcMoY plays a key role in regulating sex determination of Z. cucurbitae males. Our findings will help the understanding of sex determination in Z. cucurbitae and facilitate the development of genetic sexing strains in its biological control. The photo that depicts the morphology of a Z. cucurbitae female adult is provided by Associate Professor Lin Xianwu from the School of Plant Protection, Hainan University, China. See pages 505–513 for details

    Volume 22, Issue 1, Jan. 2023

    Early defoliation is gradually becoming a major problem that poses a threat to the pear industry in southern China, which is caused by multiple factors including abiotic and biotic stress. Notably, the occurrence of early defoliation induces the out-of-season blooming, which subsequently has negative effects on pear tree vigor, fruit quality, and sustained high yield in the following year. To investigate the cultivars resistant to early defoliation, we performed the resistance and susceptibility evaluation of 155 pear accessions response to early defoliation, which provided the important information for both cultivation protection and future breeding in pear, and the transcriptome analysis provides new insights into potentially essential genes responding to early defoliation in pears for future molecular breeding. The photo is provided by the research team of Dr. Wu Jun from Nanjing Agricultural University, China. See pages 120–138 for details.

    Volume 21, Issue 12, Dec. 2022

    Crop production and livelihoods of smallholder farmers are often threatened by crop insect pests and diseases worsening the insecurity of food. The goal of this special focus is to share knowledge on integrated pest management of four major crop diseases and one insect pest. The innovative technologies presented in the reviews offer valuable guidance and reference for sustainable control of the devastating diseases and insect pests. The cover photo is a combination of the symptoms caused by rice blast disease, fusarium head blight, maize lethal necrosis disease, potato late blight, and desert locust, which were provided by the corresponding authors of the reviews included in this special focus. See pages 3417–3487 for more details.

    Volume 21, Issue 11, Nov. 2022

    China has the largest number of sheep in the world. In order to improve the efficiency of sheep production, a complete understanding of the early-life establishment of the gastrointestinal fungal community allows us to develop better management operations and manipulate the gut microbiota for lambs, as well as provide new insight and directions for future studies in this research area. The succession process of the fungal community from birth to 4 months of age can be divided into
    3 phases: colonization, transition, and a relatively stable period of maturation. Initially, the gastrointestinal fungal communities are heterogeneous, but they become more homogeneous with the lambs’ progress to maturity. The age-related genera Acremonium, Microascus, Valsonectria, Myrmecridium, Scopulariopsis, Myrothecium, Saccharomyces, and Stephanonectria were presented in both rumen and rectum, indicating that these genera may be important in the maturity process of the fungal community. The cover photo of sheep was provided by Prof. Zhang Yingjie from College of Animal Science and Technology, Hebei Agricultural University, China. See pages 3314–3328 for more details.

    Volume 21, Issue 10, Oct. 2022

    Foxtail millet (Setaria italica (L.) Beauv.) is a minor food crop of global importance and a new model for C4 plants. YABBY genes are plant-specific transcription factors (TFs) that function in plant growth and development. To investigate the functions of the YABBY genes in plants’ stress tolerance, we analyzed the YABBY genes in foxtail millet and investigated their functions on plant growth and responses to different stresses. The objective of this study was to analyze the YABBY genes and their functions in this species at the genome-wide level. We also characterized the function of one of the YABBY genes, SiDL, in Arabidopsis. The findings provided a scientific foundation for further analysis of YABBY genes in foxtail millet. The photo is provided by the research team of Dr. Guo Jie from Shanxi Agricultural University, China. See pages 2876–2887 for details.