Key message

Role of Rubisco Activase in imparting thermotolerance to the photosynthetic apparatus under high temperature. Thus, to improve the grain filling, we need to fine tune these crucial enzymes and their regulation, which directly or indirectly affect spike photosynthesis.

Abstract

CO₂ fixation in cereals crops like bread wheat (Triticum aestivum L.) is also contributed by ear photosynthesis beside the other organs like leaves or the flag leaf. 1000-grain weight of three Indian wheat cultivars (cvs.) PBW343, K7903, and HD2329 were calculated under three treatments until maturity stage (i.e. removal of flag leaf, removal of awns and shaded spikes). We observed that awn removal showed a significant decrease in 1000-grain weight in all cultivars. To delve deeper into the biological and molecular pathways taking place underlying the awn physiology, we conducted the awn transcriptome analysis of thermosusceptible Indian wheat cv. PBW343 under heat stress (HS) at 42 °C for 2 h using RNA-sequencing (RNA-seq). Differential expression analysis revealed, 160 transcripts, out of these, 143 transcripts were significantly upregulated and 17 transcripts were repressed under HS conditions. Of these Rca1β was selected for characterization and overexpression studies. Ectopic expression of TaRca1β in rice transgenics indicate a direct correlation with tolerance under HS conditions. TaRca1β provides a better photosynthate energy partitioning under HS with a significant reduction in the non-photochemical fluorescence quenching of the photosynthetic machinery.

中文翻译：

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解码小麦芒转录组并在水稻中过表达 Ta Rca1β 以提高耐热性

关键信息

Rubisco Activase 在高温下赋予光合装置耐热性中的作用。因此，为了改善籽粒灌浆，我们需要微调这些直接或间接影响穗光合作用的关键酶及其调节。

抽象的

谷类作物如面包小麦 ( Triticum aestivum ) 中的CO _2固定L.) 除了叶或旗叶等其他器官外，还由穗光合作用贡献。三个印度小麦品种（cvs.）PBW343、K7903 和HD2329 的千粒重在三个处理直至成熟期（即去除旗叶、去除芒和阴影穗）下计算。我们观察到除芒表明所有品种的千粒重显着降低。为了深入研究芒生理学背后发生的生物学和分子途径，我们对热敏感的印度小麦品种进行了芒转录组分析。PBW343 在 42°C 的热应激 (HS) 下使用 RNA 测序 (RNA-seq) 处理 2 小时。差异表达分析显示，160 个转录本，其中 143 个转录本显着上调，17 个转录本在 HS 条件下被抑制。这些选择Rca1β用于表征和过表达研究。Ta Rca1β在水稻转基因中的异位表达表明与 HS 条件下的耐受性直接相关。Ta Rca1β在 HS 下提供了更好的光合能量分配，显着降低了光合机制的非光化学荧光猝灭。