[目的]探究水稻减数分裂期高温如何影响苯丙烷类代谢,并分析其与水稻耐热性的关系.[方法]以N22、广陆矮 15、SDWG005、全两优 681、Y两优 900、Y两优 1 号、两优培九和绵恢 101(MH101)等 8 种耐热和不耐热水稻品种为试验材料,设置常温和高温处理,分析减数分裂期高温胁迫对水稻的花粉活力与苯丙烷类代谢关键酶活性、木质素、总黄酮及总酚等主要代谢产物含量之间的相关性;并进一步选择极端耐高温的SDWG005和极端不耐高温的 MH101 为材料分析苯丙烷类代谢、碳水化合物代谢和抗氧化系统对水稻耐热性的影响.[结果]1)与对照相比,高温显著降低水稻花粉活力和颖花受精率,不同的水稻品种受高温影响后,花粉活力和颖花受精率的降幅不同.2)高温显著增加颖花中肉桂酸-4-羟化酶和 4-香豆酸辅酶A连接酶活性以及木质素、总黄酮和总酚的含量,且耐热品种增幅高于敏感品种.3)高温下花粉活力与肉桂酸-4-羟化酶活性、木质素含量显著相关,颖花受精率与木质素含量以及木质素含量与类黄酮含量极显著相关.4)与MH101 相比,SDWG005 小穗颖壳中木质素受高温显著诱导积累,且高温下能够维持较高细胞壁过氧化物酶活性.5)与MH101相比,SDWG005颖花在高温下能够维持较高过氧化物酶、超氧化物歧化酶和抗坏血酸氧化酶活性,进而减少颖花中过氧化氢和丙二醛的积累.高温下SDWG005颖花中淀粉含量更高,酸性转化酶、蔗糖合酶及ATPase基因的表达量显著增加.[结论]减数分裂期高温促进颖花中苯丙烷类代谢关键酶活性的上升和代谢产物含量的增加,耐热品种高温下能够积累较多的木质素和类黄酮,具有较高抗氧化酶活性,同时蔗糖代谢和能量产生效率较高,从而具有较强的耐热性.

KEY MESSAGE:Cytoplasm-localized RING ubiquitin E3 ligase AtCHYR2 involved in plant glucose responses during germination and post-germinative growth. CHY ZINC FINGER AND RING PROTEIN (CHYR) containing both a CHY zinc finger and a C3H2C3-type RING domain plays important roles in plant drought tolerance and the abscisic acid (ABA) response; however, their functions in sugar signaling pathways are less studied. Here, we report a glucose (Glc) response gene AtCHYR2, a homolog of RZFP34/CHYR1, which is induced by various abiotic stresses, ABA, and sugar treatments. In vitro, we demonstrated that AtCHYR2 is a cytoplasm-localized RING ubiquitin E3 ligase. Overexpression of AtCHYR2 led to hypersensitivity to Glc and enhanced Glc-mediated inhibition of cotyledon greening and post-germinative growth. Contrastingly, AtCHYR2 loss-of-function plants were insensitive to Glc-regulated seed germination and primary root growth, suggesting that AtCHYR2 is a positively regulator of the plant glucose response. Additionally, physiological analyses showed that overexpression AtCHYR2 increased stomata aperture and photosynthesis under normal condition, and promoted accumulation of endogenous soluble sugar and starch in response to high Glc. Genome-wide RNA sequencing analysis showed that AtCHYR2 affects a major proportion of Glc-responsive genes. Particularly, sugar marker gene expression analysis suggested that AtCHYR2 enhances the Glc response via a signaling pathway dependent on glucose metabolism. Taken together, our findings show that a novel RING ubiquitin E3 ligase, AtCHYR2, plays an important role in glucose responses in Arabidopsis.

Background Both the protein domains and transcript structures influence protein functional variation. The genomic location of both protein domains and transcript structural features can be described using the genomic coordinates of their encoded sequences. However, the coordinates of protein domains and transcriptional features often differ greatly, and it is difficult to view them in combination at the genome-wide level. In this paper, we describe the development of a new tool that allows users to visualize domains and transcript features together, using either built-in or uploaded genome datasets, and export publication-ready figures. Results We developed a user-friendly, independent R package and Shiny web application named “VisProDom”. VisProDom consists of a genome-wide database containing entire annotated transcripts merged with annotated protein domains from the Pfam database. The built-in dataset includes 82 files, which merge genome general feature format (GFF) annotations with rpsblast tabular outputs from protein sequence searches in the Pfam database. Multiple genomes can be simultaneously screened for protein domains or transcript names. VisProDom includes step-by-step introductions and clickable elements for ease of use. Conclusion VisProDom can display hundreds of transcripts alongside protein domains and export figures in a publication-ready format. This makes it a valuable tool for molecular evolution and comparative genomics.