Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a destructive soil-borne disease leading to huge yield loss.  We previously reported that Klebsiella variicola FH-1 could degrade atrazine herbicides, and the vegetative growth of atrazine-sensitive crops (i.e., soybean) was significantly increased in the FH-1-treated soil.  Interestingly, we found that FH-1 could promote soybean growth and induce resistance to S. sclerotiorum.  In our study, strain FH-1 could grow in a nitrogen-free environment, dissolve inorganic phosphorus and potassium, and produce indoleacetic acid and a siderophore.  The results of pot experiments showed that K. variicola FH-1 promoted soybean plant development, substantially improving plant height, fresh weight, and root length, and induced resistance against S. sclerotiorum infection in soybean leaves.  The area under the disease progression curve (AUDPC) for treatment with strain FH-1 was significantly lower than the control and was reduced by up to 42.2% within 48 h (P<0.001).  Moreover, strain FH-1 rcovered the activities of catalase, superoxide dismutase, peroxidase, phenylalanine ammonia lyase, and polyphenol oxidase, which are involved in plant protection, and reduced malondialdehyde accumulation in the leaves.  The mechanism of induction of resistance appeared to be primarily resulted from the enhancement of transcript levels of PR10, PR12, AOS, CHS, and PDF1.2 genes.  The colonization of FH-1 on soybean root, determined using CLSM and SEM, revealed that FH-1 colonized soybean root surfaces, root hairs, and exodermis to form biofilms.  In summary, K. variicola FH-1 exhibited the biological control potential by inducing resistance in soybean against S. sclerotiorum infection, providing new suggestions for green prevention and control.

Spodoptera frugiperda (Lepidoptera: Noctuidae) is an important migratory agricultural pest worldwide, which has invaded many countries in the Old World since 2016 and now poses a serious threat to world food security. The present monitoring and early warning strategies for the fall army worm (FAW) mainly focus on adult population density, but lack an information technology platform for precisely forecasting the reproductive dynamics of the adults. In this study, to identify the developmental status of the adults, we first utilized female ovarian images to extract and screen five features combined with the support vector machine (SVM) classifier and employed male testes images to obtain the testis circular features. Then, we established models for the relationship between oviposition dynamics and the developmental time of adult reproductive organs using laboratory tests. The results show that the accuracy of female ovary development stage determination reached 91%. The mean standard error (MSE) between the actual and predicted values of the ovarian developmental time was 0.2431, and the mean error rate between the actual and predicted values of the daily oviposition quantity was 12.38%. The error rate for the recognition of testis diameter was 3.25%, and the predicted and actual values of the testis developmental time in males had an MSE of 0.7734. A WeChat applet for identifying the reproductive developmental state and predicting reproduction of S. frugiperda was developed by integrating the above research results, and it is now available for use by anyone involved in plant protection. This study developed an automated method for accurately forecasting the reproductive dynamics of S. frugiperda populations, which can be helpful for the construction of a population monitoring and early warning system for use by both professional experts and local people at the county level.

Sugarcane smut caused by Sporisorium scitamineum is a destructive disease responsible for significant losses in sugarcane production worldwide. However, the mechanisms underlying the pathogenicity of this fungus remain largely unknown. In this study, we found that the disruption of the SsRSS1 gene, which encodes a salicylic acid (SA) sensing regulator, does not affect phenotypic traits such as the morphology, growth rate, and sexual mating ability of haploid basidiospores, but rather reduces the tolerance of basidiospores to SA stress by blocking the induction of SsSRG1, a gene encoding a SA response protein in S. scitamineum. SsRSS1 deletion resulted in the attenuation of the virulence of the fungus. In addition to a significant reduction in whip formation, a portion of plantlets (18.3%) inoculated with the ΔSsRSS1 strains were found to be infected but failed to produce whips for up to 90 days post-inoculation. However, the development of hyphae and teliospore from the ΔSsRSS1-infected plants that formed whips seemed indistinguishable from that in the wild-type-infected plants. Combined, our findings suggested that SsRss1 is required for maintaining fungal fitness in planta by counteracting SA stress.

Utilizing the heterosis of indica/japonica hybrid rice (IJHR) is an effective way to further increase rice grain yield.  Rational application of nitrogen (N) fertilizer plays a very important role in using the heterosis of IJHR to achieve its great yield potential.  However, the responses of the grain yield and N utilization of IJHR to N application rates and the underlying physiological mechanism remain elusive.  The purpose of this study was to clarify these issues.  Three rice cultivars currently used in rice production, an IJHR cultivar Yongyou 2640 (YY2640), a japonica cultivar Lianjing 7 (LJ-7) and an indica cultivar Yangdao 6 (YD-6), were grown in the field with six N rates (0, 100, 200, 300, 400, and 500 kg ha^–1) in 2018 and 2019.  The results showed that with the increase in N application rates, the grain yield of each test cultivar increased at first and then decreased, and the highest grain yield was at the N rate of 400 kg ha^–1 for YY2640, with a grain yield of 13.4 t ha^–1, and at 300 kg ha^–1 for LJ-7 and YD-6, with grain yields of 9.4–10.6 t ha^–1.  The grain yield and N use efficiency (NUE) of YY2640 were higher than those of LJ-7 or YD-6 at the same N rate, especially at the higher N rates.  When compared with LJ-7 or YD-6, YY2640 exhibited better physiological traits, including greater root oxidation activity and leaf photosynthetic rate, higher cytokinin content in the roots and leaves, and more remobilization of assimilates from the stem to the grain during grain filling.  The results suggest that IJHR could attain both higher grain yield and higher NUE than inbred rice at either low or high N application rates.  Improved shoot and root traits of the IJHR contribute to its higher grain yield and NUE, and a higher content of cytokinins in the IJHR plants plays a vital role in their responses to N application rates and also benefits other physiological processes. 

A major challenge in modern rice production is to achieve the dual goals of high yield and good quality with low environmental costs.  This study was designed to determine whether optimized nitrogen (N) fertilization could fulfill these multiple goals.  In two-year experiments, two high yielding ‘super’ rice cultivars were grown with different N fertilization management regimes, including zero N input, local farmers’ practice (LFP) with heavy N inputs, and optimized N fertilization (ONF).  In ONF, by reducing N input, increasing planting density, and optimizing the ratio of urea application at different stages, N use efficiency and the physicochemical and textural properties of milled rice were improved at higher yield levels.  Compared with LFP, yield and partial factor productivity of applied N (PFP) under ONF were increased (on average) by 1.70 and 13.06%, respectively.  ONF increased starch and amylose content, and significantly decreased protein content.  The contents of the short chains of A chain (degree of polymerization (DP) 6–12) and B1 chain (DP 13–25) of amylopectin were significantly increased under ONF, which resulted in a decrease in the stability of rice starch crystals.  ONF increased viscosity values and improved the thermodynamic properties of starch, which resulted in better eating and cooking quality of the rice.  Thus, ONF could substantially compensate the negative effects caused by N fertilizer and achieve the multiple goals of higher grain quality and nitrogen use efficiency (NUE) at high yield levels.  These results will be useful for applications of high quality rice production at high yield levels.

Single-step genomic best linear unbiased prediction (ssGBLUP) is now intensively investigated and widely used in livestock breeding due to its beneficial feature of combining information from both genotyped and ungenotyped individuals in the single model.  With the increasing accessibility of whole-genome sequence (WGS) data at the population level, more attention is being paid to the usage of WGS data in ssGBLUP.  The predictive ability of ssGBLUP using WGS data might be improved by incorporating biological knowledge from public databases.  Thus, we extended ssGBLUP, incorporated genomic annotation information into the model, and evaluated them using a yellow-feathered chicken population as the examples.  The chicken population consisted of 1 338 birds with 23 traits, where imputed WGS data including 5 127 612 single nucleotide polymorphisms (SNPs) are available for 895 birds.  Considering different combinations of annotation information and models, original ssGBLUP, haplotype-based ssGHBLUP, and four extended ssGBLUP incorporating genomic annotation models were evaluated.  Based on the genomic annotation (GRCg6a) of chickens, 3 155 524 and 94 837 SNPs were mapped to genic and exonic regions, respectively.  Extended ssGBLUP using genic/exonic SNPs outperformed other models with respect to predictive ability in 15 out of 23 traits, and their advantages ranged from 2.5 to 6.1% compared with original ssGBLUP.  In addition, to further enhance the performance of genomic prediction with imputed WGS data, we investigated the genotyping strategies of reference population on ssGBLUP in the chicken population.  Comparing two strategies of individual selection for genotyping in the reference population, the strategy of evenly selection by family (SBF) performed slightly better than random selection in most situations.  Overall, we extended genomic prediction models that can comprehensively utilize WGS data and genomic annotation information in the framework of ssGBLUP, and validated the idea that properly handling the genomic annotation information and WGS data increased the predictive ability of ssGBLUP.  Moreover, while using WGS data, the genotyping strategy of maximizing the expected genetic relationship between the reference and candidate population could further improve the predictive ability of ssGBLUP.  The results from this study shed light on the comprehensive usage of genomic annotation information in WGS-based single-step genomic prediction.

The basidiomycetous fungus Sporisorium scitamineum causes sugarcane smut that leads to severe economic losses in the major sugarcane growing areas in China, India and Brazil, etc.  Autophagy is a conserved pathway in eukaryotes for bulk degradation and cellular recycling, and was shown to be important for fungal cell growth, development, and pathogenicity.  However, physiological function of autophagy has not been studied in S. scitamineum.  In this study, we identified a conserved Atg8 protein, named as SsAtg8 and characterized its function. Our results showed that autophagy was blocked in the ssatg8Δ mutant, in nitrogen starvation.  The ssatg8Δ mutant formed pseudohypha frequently and was hypersensitive to oxidative stress.  However, mating or filamenation was unaffected in the ssatg8Δ mutant in vitro.  Overall we demonstrate that autophagy is dispensable for S. scitamineum mating/filamentation, while critical for oxidative stress tolerance and proper morphology in sporidial stage.   

This study aimed to determine the effect of stage and level of feed intake on energy metabolism, carbon-nitrogen (C-N) balance, and methane emission to determine energy and protein requirements for maintenance of maternal body including pregnancy tissues during pregnancy using the method of C-N balance.  Twenty-one ewes carrying twin fetuses were randomly divided into three groups of seven ewes each in the digestion and respirometry trial at d 40, 100, and 130 of gestation, respectively.  Three groups were fed a mixed diet either for ad libitum intake, 70 or 50% of the ad libitum intake during pregnancy.  The results showed that the apparent digestibility of C and N were increased as feeding levels decreased at each stage of gestation.  The daily net energy requirements for maintenance (NE_m) were 295.80, 310.09, and 323.59 kJ kg^–1 BW^0.75 (metabolic body weight) with a partial efficiency of metabolisable energy utilization for maintenance of 0.664, 0.644, and 0.620 at d 40, 100, and 130 of gestation, respectively.  The daily net protein requirements for maintenance were 1.99, 2.35, and 2.99 g kg^–1 BW^0.75 at d 40, 100, and 130 of gestation, respectively.  These results for the nutritional requirements of the net energy and protein may help to formulate more balanced diets for Hu sheep during pregnancy.

Granulosa cells (GCs) are somatic cells of ovary, the behaviors of GCs are important for ovarian function.  MicroRNAs (miRNAs) are a class of endogenous 18–24 nucleotide (nt) non-coding RNAs, some of which have been shown to be important regulators of GCs function.  miR-34c involved in the regulation of various biological processes and was identified to be a pro-apoptotic and anti-proliferative factor in many cell types.  However, the roles of miR-34c in GCs function remain unknown.  In this study, we used Annexin V-FITC and EdU assays to demonstrate that miR-34c exerted pro-apoptotic and anti-proliferative effects in porcine GCs.  Dual-luciferase reporter assays, quantitative real-time PCR (qRT-PCR) and Western blotting identified Forkhead box O3a (FoxO3a) as a direct target gene of miR-34c.  The overexpression of FoxO3a rescued the phenotypic change caused by miR-34c in porcine GCs.  In conclusion, miR-34c regulate the function of porcine GCs by targeting FoxO3a.

    The enzyme Δ³,Δ²-dienoyl-CoA isomerase (ECI1) plays a crucial role in the mitochondrial β-oxidation of fatty acids with a double-bond in odd and even positions. The ECI1 gene might be a qualified candidate for studies pertaining to lipid deposition and meat quality in swine. In the present study, ECI1 cDNA of the Tibetan pig was obtained by in silico cloning and verified by PCR analysis. Single-nucleotide polymorphisms (SNPs) of ECI1 were screened by PCR-sequencing and genotypes of those SNPs were tested by PCR-restriction fragment length polymorphism (PCR-RFLP) in Diannan small-ear pigs (DSP, n=40), Tibetan pigs (TP, n=60) and Yorkshire pigs (YP, n=30). The expression levels of ECI1 were analyzed by real-time quantitative PCR and Western blotting in tissues of the liver, backfat, and longissimus dorsi (LD) muscle of DSP (n=8), TP (n=8) and YP (n=8). Single factor linear correlation analysis was applied separately for each breed to evaluate correlations between ECI1 gene expression in the LD muscle and intramuscular fat (IMF) content. We obtained an ECI1 gene length of 1 401 bp from the cDNA that contained a full coding region of 909 bp. Three novel SNPs (g.42425337G>A; g.42424666A>G; and g.42422755A>G) were detected, and only g.42424666A>G exhibited three genotypes among the three breeds. The ECI1 expression levels in the LD muscle of DSP and TP were significantly higher than that of YP (P<0.05). Moreover, TP had the highest ECI1 expression in backfat (P<0.01), and a positive correlation was observed between gene expression and IMF content. The results suggest that differences in ECI1 gene expression might be related to lipid deposition and meat quality in pig.

This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency (WUE) under alternate wetting and drying (AWD) irrigation than check rice.  Two super rice cultivars and two elite check rice cultivars were grown in pots with three soil moisture levels, well watered (WW), moderate water deficit (MWD) and severe water deficit (SWD).  Two cultivars, each for super rice and check rice, were grown in field with three irrigation regimes, alternate wetting and moderate drying (AWMD), alternate wetting and severe drying (AWSD) and conventional irrigation (CI).  Compared with that under WW, grain yield was significantly decreased under MWD and SWD treatments, with less reduction for super rice than for check rice.  Super rice had higher percentage of productive tillers, deeper root distribution, higher root oxidation activity, and greater aboveground biomass production at mid and late growth stages than check rice, especially under WMD and WSD.  Compared with CI, AWMD increased, whereas AWSD decreased grain yield, with more increase or less decrease for super rice than for check rice.  Both MWD and SWD treatments and either AWMD or AWSD regime significantly increased WUE compared with WW treatment or CI regime, with more increase for super rice than for check rice.  The results suggest that super rice has a stronger ability to cope with soil water deficit and holds greater promising to increase both grain yield and WUE by adoption of moderate AWD irrigation.

   MicroRNAs (miRNAs) are endogenous 18–24 nucleotide (nt) non-coding RNAs, some of which have been indicated to play key roles in granulosa cells (GCs) function. However, little is known about how the miRNA gene expression itself is regulated in the GCs. Our previous study showed that miR-34c, identified to be a pro-apoptotic and anti-proliferative factor in many cell types, exerted the same effects in porcine GCs. Here, the transcriptional regulation of miR-34c expression in GCs was further investigated. 5´ rapid amplification of cDNA ends (RACE) assay indicated that the pri-miR-34c transcription start site was located in 1 556 bp upstream of pre-miR-34c. With dual-luciferase reporter assay, we confirmed a 69 bp core promoter region (–1 799 bp/–1 730 bp) was indispensable for the transcription of miR-34c. Chromatin immunoprecipitation (ChIP) assay demonstrated that p53, p50, and p65 could bind to the transcription factor binding sites within the 69 bp core promoter region. In addition, deletion of transcripition factor binding sites resulted in obvious change of the miR-34c promoter activity. Finally, using overexpression and knockdown of p53, p50, and p65 strategies, we showed that p53 and p50 could positively regulated miR-34c expression, whereas p65 neletively regulated miR-34c expression in GCs. Our results provide new data about the transcription regulatory mechanism of miRNA genes in GCs.

    The objectives of this study were to estimate the genetic parameters and the breeding progress in a Landrace herd in China, and to predict the potential benefits by applying new breeding technology. Hereby, the performance records from a Landrace swine herd in China, composing over 33 000 pigs born between 2001 and 2013, were collected on six economically important traits, i.e., average daily gain between 30–100 kg (ADG), adjusted backfat thickness at 100 kg (BF), adjusted days to 30 kg (D30), adjusted days to 100 kg (D100), number born alive (NBA), and total number born (TNB). The genetic parameters were estimated by restricted maximum likelihood via DMU, and realized genetic trends were analyzed. Based on the real population structure and genetic parameters obtained from this herd, the potential genetic trends by applying genomic selection (GS) were predicted via a computer simulation study. Results showed that the heritability estimates in this Landrace herd were 0.55 (0.02), 0.42 (0.01), and 0.12 (0.01), for BF, D100, and TNB, respectively. Favorable genetic trends were obtained for D100, BF, and TNB due to direct selection, for ADG and NBA due to indirect selection. Long-term selection against D100 did not improve D30, though they are highly genetically correlated (0.64). Appling GS in such a swine herd, the genetic gain can be increased by 25%, or even larger for traits with low heritability or individuals without phenotypes before selection. It can be concluded that conventional breeding strategy was effective in the herd studied, while applying GS is promising and hence the road ahead in swine breeding.

Knowledge on the performance in grain yield and physiological traits is essential to understand the main yield-limiting factor and make strategies for breeding and crop management in rice (Oryza sativa L.). This study investigated the changes in grain yield and associated physiological traits of rice in the Yangtze River Basin of China during the last 60 yr. Thirteen mid-season indica and 12 japonica rice cultivars that were popularly used were grown in the field in 2008 and 2009. The grain yield and yield components, biomass, leaf area, leaf photosynthesis, root oxidation activity, and harvest index were examined. The results showed that grain yield and grain yield per day have progressively increased during the years and such increases are mainly attributed to the expanded sink size as a result of more spikelets per panicle, especially for the case of super rice. Both biomass and harvest index were increased with the improvement of cultivars. Increase in biomass for modern rice cultivars was associated with an enhancement of leaf area and photosynthesis, root dry weight, and root oxidation activity, although the indica super rice cultivars showed a lower leaf photosynthetic rate and root oxidation activity than the semi-dwarf cultivars during the grain filling period. Both indica and japonica super rice cultivars exhibited a low percentage of filled grains, which may limit their great yield potential. All the data suggested that grain yield have been substantially improved during the 60 yr of rice breeding in the Yangtze River Basin. Expanded sink size, increased dry matter production and harvest index, and enhanced leaf area and photosynthesis, root dry weight, and root oxidation activity contribute to the improvement in grain yield. Increase in filling efficiency could realize the great yield potential in super rice.

Root system is a vital part of plant and regulates many aspects of shoot growth and development. This paper reviews how some traits of root morphology and physiology are related to the formation of grain yield in rice (Oryza sativa L.). Higher root biomass, root oxidation activity, and cytokinin contents in roots are required for achieving more panicle number, more spikelets per panicle, greater grain-filling percentage, and higher grain yield. However, these root traits are not linearly correlated with yield components. When these traits reach very high levels, grain filling and grain yield are not necessarily enhanced. High numbers of mitochondria, Golgi bodies, and amyloplasts in root tip cells benefit root and shoot growth and yield formation. Proper crop management, such as an alternate wetting and moderate soil drying irrigation, can significantly improve ultra-structure of root tip cells, increase root length density and concentration of cytokinins in root bleedings, and consequently, increase grain-filling percentage, grain yield, and water use efficiency. Further studies are needed to investigate the mechanism underlying root-shoot and root-soil interactions for high grain yield, the roles of root-sourced hormones in regulating crop growth and development and the effects of soil moisture and nutrient management on the root architecture and physiology.

Since the combining ability was proposed in 1942, efforts to uncover the genetic basis underlying this phenomenon have been ongoing for nearly 70 yr, with little success. Some breeding strategies based on evaluation of combining ability have been produced, and are still extensively used in hybrid breeding. In this review, the genetic basis underlying these breeding strategies is discussed, and a potential genetic control of general combining ability (GCA) is postulated. We suggested that GCA and the yields of inbred lines might be genetically controlled by different sets of loci on the maize genome that are transmitted into offspring. Different inbred lines might possess different favorable alleles for GCA. In hybrids, loci involved in multiple pathways, which are directly or indirectly associated with yield performance, might be regulated by GCA loci. In addition, a case of GCA mapping using a set of testcross progeny from introgression lines is provided.