Yang Hong, Li Yongpeng, Qiao Yunzhou, Sun Hongyong, Liu Wenwen, Qiao Wenjun, Li Weiqiang, Liu Mengyu, Dong Baodi
Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-Saving, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, China.
College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.
Plant Cell Environ. 2023 May;46(5):1562-1581. doi: 10.1111/pce.14548. Epub 2023 Feb 1.
Low light stress seriously decreased wheat grain number through the formation of aborted spike during the reproductive period and induced new tiller regeneration to offset the loss of grain number. However, the mechanism by which plants coordinate spike aborted growth and the regeneration of new tillers remains unknown. To better understand this coordinated process, morphological, physiological and transcriptomic analyses were performed under low light stress at the young microspore stage. Our findings indicated that leaves exhausted most stored carbohydrates in 1 day of darkness. However, spike and uppermost internode (UI) were converted from sink to source, due to increased abscisic acid (ABA) content and decreased cytokinin content. During this process, genes encoding amylases, Sugars Will Eventually be Exported Transporters (SWEET) and sucrose transporters or sucrose carriers (SUT/SUC) were upregulated in spike and UI, which degraded starch into soluble sugars and loaded them into the phloem. Subsequently, soluble sugars were transported to tiller node (TN) where cytokinin and auxin content increased and ABA content decreased, followed by unloading into TN cells by upregulated cell wall invertase (CWINV) genes and highly expressed H /hexose symporter genes. Finally, expansin genes integrated the sugar pathway and hormone pathway, and regulate the formation of new tillers directly.
弱光胁迫通过在生殖期形成败育穗严重降低了小麦粒数，并诱导新分蘖再生以抵消粒数损失。然而，植物协调穗败育生长和新分蘖再生的机制尚不清楚。为了更好地理解这一协调过程，在幼嫩小孢子阶段的弱光胁迫下进行了形态学、生理学和转录组分析。我们的研究结果表明，叶片在1天的黑暗中耗尽了大部分储存的碳水化合物。然而，由于脱落酸（ABA）含量增加和细胞分裂素含量降低，穗和最上部节间（UI）从库转变为源。在此过程中，编码淀粉酶、糖最终输出转运蛋白（SWEET）以及蔗糖转运蛋白或蔗糖载体（SUT/SUC）的基因在穗和UI中上调，这些基因将淀粉降解为可溶性糖并将其装载到韧皮部中。随后，可溶性糖被运输到分蘖节（TN），在那里细胞分裂素和生长素含量增加而ABA含量降低，随后通过上调的细胞壁转化酶（CWINV）基因和高表达的H/己糖同向转运蛋白基因卸载到TN细胞中。最后，扩张蛋白基因整合了糖途径和激素途径，并直接调节新分蘖的形成。
