杂交小麦应用是未来提高小麦产量的一种途径，当前部分杂交小麦品种株高的增加在一定程度上加大了其倒伏风险。本研究以两个抗倒伏性不同的杂交组合为试验材料，通过分析不同灌浆时期茎秆相关性状变化、基部第二节间转录组和代谢组数据及基部第二节间木质素合成积累等揭示其抗倒伏差异的形成机制。结果表明，抗倒伏杂交组合茎秆相关性状，如茎秆抗折力、穿刺强度、茎秆充实度及木质素含量（含G和S型单体）均显著高于倒伏敏感性组合。KEGG富集分析表明，灌浆后期差异代谢物和差异表达基因主要被显著富集到苯丙烷生物合成途径。本试验共鉴定了35个参与苯丙烷途径的关键调控基因，其中42%的基因在灌浆后期显著差异表达，且在显著差异表达基因中，超过80%的基因在抗倒伏组合中的表达显著高于其在倒伏敏感组合中的表达，而抗倒伏组合木质素合成途径中松柏醛、阿魏酸和松柏醇等中间代谢物显著低于倒伏敏感组合。综合分析表明，抗倒伏组合灌浆后期仍具有较高抗倒伏能力的关键在于其具有较高的木质素合成能力。本试验还通过对已审定杂交小麦和常规小麦品种的茎秆特征比较，提出了培育抗倒伏杂交小麦组合应关注的茎秆性状。

小麦-玉米轮作体系减磷措施调控土壤磷素有效性与微生物间的耦合机制研究鲜有报道。本研究基于初始高磷（30.36 mg kg^-1）和低磷水平（9.78 mg kg^-1）石灰性土壤，通过连续四季的盆栽试验（2016-2018），探究小麦-玉米轮作体系仅麦季施磷（Pw）较常规麦-玉两季均施磷肥（Pwm）措施对作物产量、土壤有效磷和微生物群落结构的影响。结果表明，高磷水平Pw处理较Pwm处理每年减少33.3%的磷肥投入情况下，作物总产量能够连续两年稳产。玉米大喇叭口期，Pw处理土壤水溶性磷浓度与Pwm处理含量无显著差异。土壤磷含量显着影响土壤微生物群落，尤其是真菌群落。Pw处理变形菌门的相对丰度和碱性磷酸酶（ALP）活性显著高于Pwm处理（分别为11.4和13.3％）。高磷水平下，土壤微生物对产量的贡献大于土壤有效磷的影响。Pw处理芽孢杆菌和根瘤菌相对丰度显著高于Pwm处理。芽孢杆菌与酸性磷酸酶（ACP）活性呈显着正相关，根瘤菌与ACP和ALP活性均呈显着正相关，可能利于土壤磷素活化。本研究说明高磷土壤条件下，小麦-玉米轮作体系仅麦季施磷可通过土壤磷有效性与微生物间的耦合实现全年作物稳产。

随着杂交小麦的应用面积逐渐增加，倒伏正在成为其获得高产的主要限制因素之一。然而，关于茎秆相关性状的配合力及其与抗倒伏杂种优势形成的研究较少。本研究，按照不完全双列杂交设计（NCII），以茎秆相关性状显著差异的3个不育系（母本）和8个恢复系（父本）为试验材料，配置24个杂交组合。对基部第二节间长度、基部第二节间抗折力等茎秆相关的8个性状开展主成分分析（PCA）、配合力分析及杂种优势分析。PCA结果表明，8个变量可被提取为两个主要因子，分别为正相关因子（因子1）和负相关因子（因子2），分别解释总变异的52.3％和33.2％。PCA和指标权重分析表明，因子1相关性状在抗倒伏优势形成中起主要作用，研究还表明，茎秆相关性状的遗传以加性效应为主。以恢复系R1，R4，R6及R7与不育系M3配置组合可获得具有较高抗倒伏能力的杂交组合，与其因子2相关性状具有较低的一般配合力效应（GCA），及因子1相关性状具有较高的GCA密切相关。杂种优势分析表明，因子1相关性状（除基部第二节间壁厚外）的GCA或特殊配合力效应（SCA）与抗倒伏杂种优势呈正相关关系。一般而言，抗倒伏杂种优势与不育系因子1相关性状GCA的相关系数显著高于其与恢复系的，此外，不育系因子1相关性状具有更高的方差值，表明，在配置杂交组合时应特别关注不育系因子1相关性状的选择。遗传分析表明，基部第二节间直径和重心高度的狭义遗传力明显低于其他性状（<60％），表明，在亲本选育时这两个性状适合在高世代进行选择。这些发现可为亲本选育和抗倒伏杂种优势的利用提供理论依据。

Because of the yield increase of 3.5–15% compared to conventional wheat, hybrid wheat is considered to be one of the main ways to greatly improve the wheat yield in the future.  In this study, we performed a principal component analysis (PCA) on two-line hybrids wheat and their parents using the grain weight (GW), the length of spike (LS), the kernel number of spike (KSN), and spike number (SPN) as variables.  The results showed that the variables could be classified into three main factors, the weight factor (factor 1), the quantity factor 1 (factor 2) and the quantity factor 2 (factor 3), which accounted for 37.1, 22.6 and 18.5%, respectively of the total variance in different agronomic variables, suggesting that the GW is an important indicator for evaluating hybrid combinations, and the grain weight of restorer line (RGW) could be used as a reference for parents selection.  The hybrid combination with a higher score in factor 1 direction and larger mid-parent heterosis (MPH) of the GW and its parents were used to carry out the analysis of grain filling, 1-aminocylopropane-1-carboxylicacid (ACC) and polyamine synthesis related genes.  The results suggested that the GW of superior grain was significantly higher than that of inferior grains in BS1453×JS1 (H) and its parents.  Both grain types showed a weight of H between BS1453 (M) and JS1(R), and a larger MPH, which may be caused by their differences in the active filling stage and the grain filling rate.  The ADP-glucose pyrophosphorylase (AGPase), granule bound starch synthase I (GBSSI), starch synthase III (SSS), and starch branching enzyme-I (SBE-I) expression levels of H were intermediated between M and R, which might be closely related to MPH formation of the GW.  Compared with R and H, the GW of M at maturity was the lowest.  The expression levels of spermidine synthase 2 (Spd2), ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) had significantly positive correlations with the grain filling rate (r=0.77*, 0.51*, 0.59*), suggesting their major roles in the grain filling and heterosis formation.  These provide a theoretical basis for improving the GW of photo-thermo-sensitive male sterile lines (PTSMSL) by changing the endogenous polyamine synthesis in commercial applications.

Rapeseed is a very important oil crop in China; however, its production is challenging due to the absence of effective weed management strategies.  This is predominantly because of a shortage of herbicide resistance genes.  Acetohydroxyacid synthase (AHAS) herbicides inhibit AHAS, a key enzyme involved in branched-chain amino acid synthesis that is required for plant growth.  A rapeseed line designated M342 with AHAS herbicide resistance was developed through seed mutagenesis and was studied to assess the level and mode of inheritance of the resistance and to identify the molecular basis of resistance.  M342 possessed a high level of cross-resistance to sulfonylureas (SUs) and imidazolinones (IMIs).  This resistance was due to AHAS insensitivity to these herbicides and was inherited as a dominant trait conferred by a single nuclear-encoded gene.  Molecular analysis revealed the presence of a Trp574Leu mutation in M342, and an allele-specific cleaved amplified polymorphic sequence (AS-CAPS) marker was developed and cosegregated with herbicide resistance in the F₂, BC₁, and BC₂ populations.  This mutation altered the transcript levels of BnAHAS1 and BnAHAS3 in M342 compared with those in the wild type, but it did not affect the agronomic or quality traits.  The simple genetic inheritance of this mutation and the availability of the cleaved amplified polymorphic sequence (CAPS) marker and herbicide resistance gene should facilitate the development of herbicide-resistant rapeseed cultivars for effective weed control in China.  

This study investigated the effects of the degree of unsaturation (unsaturity) of long-chain fatty acids on microbial protein content and the activities of transaminases and dehydrogenase in vitro using goat rumen fluid as the cultural medium. Six types of fatty acids, stearic acid (C18:0, group A, control group), oleic acid (C18:1, n-9, group B), linoleic acid (C18:2, n-6, group C), α-linolenic acid (C18:3, n-3, group D), arachidonic acid (C20:4, n-6, group E), and eicosapentaenoic acid (C20:5, n-3, group F), were tested, and the inclusion ratio of each fatty acid was 3% (w/w) in total of culture substrate. Samples were taken at 0, 3, 6, 9, 12, 18 and 24 h, respectively, during culture for analyses. Compared with stearic acid, linoleic acid, α-linolenic acid, and arachidonic acid increased the bacterial protein content, while oleic acid and eicosapentaenoic acid had no significant effects; the protozoal protein content was reduced for all the unsaturated fatty acids, and the magnitude of the reduction appeared to be associated with the degree of unsaturity of fatty acids. The total microbial protein content was dominantly accounted by the protozoal protein content (about 4–9 folds of the bacterial protein), and only increased by linoleic acid, but reduced by oleic acid, arachidonic acid and eicosapentaenoic acid. There were no significant effects in the activities of both glutamic oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) for all the other fatty acids, except for arachidonic acid which enhanced GOT activity and oleic acid which enhanced GPT activity. The total dehydrogenase activity was positively correlated with the degree of unsaturation of fatty acids. In conclusion, the inclusion of 3% of long-chain unsaturated fatty acids increased bacterial protein content, whereas reduced protozoal protein content and enhanced dehydrogenase activity. The fatty acids with more than three double bonds had detrimental effects on the microbial protein content. This work demonstrates for the first time the effect rule of the unsaturation degree of long-chain fatty acids on the rumen microbial protein in vitro.

    This study investigated the impacts of the degree of unsaturation (unsaturity) of long-chain fatty acids on volatile fatty acid (VFA) profiles of rumen fermentation in vitro. Six types of long-chain fatty acids, including stearic acid (C18:0, control group), oleic acid (C18:1, n-9), linoleic acid (C18:2, n-6), α-linolenic acid (C18:3, n-3), arachidonic acid (C20:4, n-6) and eicosapentaenoic acid (C20:5, n-3), were tested. Rumen fluid from three goats fitted with ruminal fistulae was used as inoculum and the inclusion rate of long-chain fatty acid was at 3% (w/w) of substrate. Samples were taken for VFA analysis at 0, 3, 6, 9, 12, 18 and 24 h of incubation, respectively. The analysis showed that there were significant differences in the total VFA among treatments, sampling time points, and treatment×time point interactions (P<0.01). α-Linolenic acid had the highest total VFA (P<0.01) among different long-chain fatty acids tested. The molar proportion of acetate in total VFA significantly differed among treatments (P<0.01) and sampling time points (P<0.01), but not treatment×time point interactions (P>0.05). In contrast, the molar proportion of propionate did not differ among treatments during the whole incubation (P>0.05). However, for butyrate molar proportions, significant differences were found not only among sampling time points but also among treatments and treatment×time point interactions (P<0.01), with eicosapentaenoic acid having the highest value (P<0.01). Additionally, no statistically significant differences were found in the acetate to propionate ratios among treatments groups (P>0.05), even the treatments stearic acid and α-linolenic acid were numerically higher than the others. The inclusion of 3% long-chain unsaturated fatty acids differing in the degree of unsaturation brought out a significant quadratic regression relation between the total VFA concentration and the double bond number of fatty acid. In conclusion, the α-linolenic acid with 3 double bonds appeared better for improving rumen microbial fermentation and the total VFA concentration.

MicroRNAs (miRNAs) are ~21 nucleotide (nt), endogenous RNAs that regulate gene expression in plants. Increasing evidence suggests that miRNAs play an important role in species-specific development in plants. However, the detailed miRNA profile divergence has not been performed among tomato species. In this study, the small RNA (sRNA) profiles of Solanum lycopersicum cultivar 9706 and Solanum habrochaites species PI 134417 were obtained by deep sequencing. Sixty-three known miRNA families were identified from these two species, of which 39 were common. Further miRNA profile comparison showed that 24 known non-conserved miRNA families were species-specific between these two tomato species. In addition, six conserved miRNA families displayed an apparent divergent expression pattern between the two tomato species. Our results suggested that species-specific, non-conserved miRNAs and divergent expression of conserved miRNAs might contribute to developmental changes and phenotypic variation between the two tomato species. Twenty new miRNAs were also identified in S. lycopersicum. This research significantly increases the number of known miRNA families in tomato and provides the first set of small RNAs in S. habrochaites. It also suggests that miRNAs have an important role in species-specific plant developmental regulation.

In order to determine the potential for haploid induction via in vitro gynogenesis in tomato, the ovules and protoplasts of embryo sacs from the hybrids Zhongza 101 and Zhongza 105 were cultured. An efficient method of ovule isolation was established in this study. Using this method, 100-150 ovules could be isolated from one ovary. Isolated ovules were cultured on three induction media to induce gynogenesis in vitro. During culture, ovules were enlarged markedly, with opaque white color. When observed microscopically, there were cell divisions and cell clumps in embryo sacs. Subsequently, the cell clumps in embryo sacs ceased growth, likely because the integument grew faster than embryo sacs did and hindered the further development of embryo sacs. Therefore, subsequent callus morphogenesis might be originated from the integument. Thousands of calli from the two tomato varieties were obtained. Five diploid plants were regenerated after 15 months of subculturing. To eliminate the hindering effect of integument on embryo sac cells, the protoplasts of embryo sacs were prepared and cultured. After 48 hours of culture, the protoplasts of embryo sacs doubled in size and gradually formed clusters of cells. These results suggested that gynogenesis might be a potential way for haploid induction in tomato.