Low light stress promotes new tiller regeneration by changing source-sink relationship and activating expression of expansin genes in wheat
Low light stress promotes new tiller regeneration by changing source-sink relationship and activating expression of expansin genes in wheat
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DOI：
10.1111/pce.14548
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发表时间：
2023-02-01
影响因子：
7.3
通讯作者：
Dong，Baodi
中科院分区：
文献类型：
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作者：
Yang，Hong;Li，Yongpeng;Dong，Baodi
弱光胁迫通过在生殖生长期形成败育穗，严重减少小麦籽粒数，并诱导新的分蘖再生，以弥补籽粒数的损失。然而，植物协调穗败育生长和新分蘖再生的机制仍然未知。为了更好地理解这一协调过程，在幼小孢子阶段的弱光胁迫下进行了形态学、生理学和转录组学分析。我们的研究结果表明，叶片消耗了大部分储存的碳水化合物在1天的黑暗。然而，由于脱落酸（阿坝）含量增加和细胞分裂素含量减少，穗部和最上部节间（UI）从库转变为源。在此过程中，淀粉酶、糖最终输出转运蛋白（SWEET）和蔗糖转运蛋白或蔗糖载体（SUT/SUC）基因在穗和UI中表达上调，将淀粉降解为可溶性糖并将其装载到韧皮部。随后，可溶性糖被运输到分蘖节（TN），细胞分裂素和生长素含量增加，阿坝含量下降，随后卸载到TN细胞的上调细胞壁转化酶（CWINV）基因和高表达H+/己糖共运输体基因。最后，扩展蛋白基因整合了糖途径和激素途径，直接调控新分蘖的形成。
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.