连阴雨天气导致田间湿度增大，诱发田间霉菌的生长繁殖，并侵染农作物导致田间霉变的发生。在大豆生长后期，因连阴雨天气导致的田间霉变严重影响大豆的产量和品质。为探究田间霉变诱导大豆品质劣变的机制，本研究利用人工降雨室模拟连阴雨天气，诱发大豆籽粒田间霉变，结合转录组学和多种代谢检测平台，解析田间霉变胁迫下大豆品质劣变的生化机理。研究结果表明，田间霉变影响大豆的外观品质，霉变大豆籽粒皱缩、变形，并出现霉斑。田间霉变使大豆籽粒中蛋白质、多糖等储藏性物质的含量降低，导致籽粒百粒重显著下降。转录组分析发现，田间霉变使大豆籽粒中氨基酸代谢、糖酵解、三羧酸循环、脂肪酸β氧化等初生代谢过程加强。代谢组分析结果也表明，霉变大豆籽粒中多种氨基酸、糖类物质、有机酸的含量显著增加，而脂肪酸的含量则显著下降。与此同时，大豆异黄酮作为一类重要的抗逆活性物质，其生物合成在转录水平和代谢水平均受到田间霉变的诱导。田间霉变诱发大豆籽粒的防御机制，通过分解和消耗储藏性物质为防御体系的构建提供能量和底物，但储藏性物质的消耗导致了大豆品质劣变。本研究为深入了解大豆籽粒田间霉变的机制提供了重要的理论基础，同时也为抗田间霉变大豆品种的筛选指明方向。

During meiosis in flowering plants, degradation of the callose wall in tetrads releases newly produced microspores, which develop into mature pollen grains. In this study, we identified zbs1, a male-sterile mutant of naked oat (Avena nuda L.) that displayed complete spikelet sterility due to inviable mature pollen. The abnormal pollen grains originated from microspores with a defective callose wall and cell plate during meiosis. The defective callose wall and cell plate of the zbs1 mutant were detected by the labeling of cell wall epitopes (β-1,3-glucan) with immunogold during meiosis, and an abnormal chromosome configuration was observed by propidium iodide staining. The mature pollen grains of the zbs1 mutant were irregular in shape, and abnormal germination was observed by scanning electron microscopy. Together, our results indicate that the cause of male sterility in zbs1 is abnormal meiosis.

Glyphosate has been used worldwide for nearly 40 years, and 30 types of resistant weeds have been reported. Glyphosate is mass-produced and widely used in China, but few studies and reports on glyphosate-resistant weeds and resistance mechanisms exist. Previous studies found a goosegrass species with high glyphosate resistance from orchards in South China and its glyphosate resistant mechanism was described in this study. The cDNA of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, EC 2.5.1.19), the target enzyme of glyphosate, was cloned from the glyphosate-resistant and -susceptible goosegrass, respectively, and referred as EPSPS-R and EPSPS-S. The Pro106 residue was known to be involved in the glyphosate resistance in most goosegrass populations. However, sequence analysis did not find the mutation at the Pro106 residue in the R biotype EPSPS amino acid sequence. The residue 133 and 382 was mutated in the R biotype EPSPS amino acid sequence instead, but it did not affect the EPSPS-S and EPSPS-R genes sensitivities to glyphosate. RT-PCR and Western blot analyses suggested that EPSPS mRNA and protein are mainly present in the shoot tissues both in the R and S goosegrass biotypes. The EPSPS-R rapidly responds to the glyphosate in R-biotype goosegrass and the induced expression was detected at 12 h post glyphosate treatment. The mRNA and protein expression of EPSPS-R increased constantly as the increasing concentration of glyphosate. However, the expression of the EPSPS-S was not induced significantly by glyphosate in the S goosegrass biotype. Quantification of real-time PCR results showed that the copy number of the EPSPS in R-biotype goosegrass was 4.7 times higher than that in the S goosegrass biotype. All the results implied that EPSPS gene amplification might mainly caused the glyphosate resistance of a goosegrass population collected from orchards in South China.

The rapid detection of glyphosate resistance in goosegrass (Eleusine indica) will enhance our ability to respond to new resistant populations of this major weed. Chlorophyll fluorescence (Fluo) and P700 (reaction center chlorophyll of photosystem I) absorbance were analyzed in one biotype of goosegrass that is resistant to glyphosate and in another that remains sensitive to the herbicide. Both biotypes were treated with a foliar spray of glyphosate. Differences in photosystem II maximum quantum yield (Fv/Fm), effective photochemical quantum yield (Y(II)), and non-photochemical quenching (NPQ) between the biotypes increased over time. Values for Fv/Fm and Y(II) differed between the two biotypes 24 h after treatment (HAT). Differentiated activities and energy dissipation processes of photosystem II (PSII) and energy dissipation processes of photosystem I (PSI) were manifested in the two biotypes 24 HAT with 20 mmol L–1 glyphosate. Differentiated energy dissipation processes of PSI were still apparent 24 HAT with 200 mmol L–1 glyphosate. These results indicate that the Fluo parameters related to PSII activity and energy dissipation and the P700 parameters related to energy dissipation are suitable indicators that enable rapid detection of glyphosate resistance in goosegrass.