Trehalose 6-Phosphate Regulates Photosynthesis and Assimilate Partitioning in Reproductive Tissue.
Trehalose 6-Phosphate Regulates Photosynthesis and Assimilate Partitioning in Reproductive Tissue.
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DOI：
10.1104/pp.17.01673
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发表时间：
2018-04
期刊：
影响因子：
7.4
通讯作者：
Paul MJ
中科院分区：
文献类型：
--
作者：
Oszvald M;Primavesi LF;Griffiths CA;Cohn J;Basu SS;Nuccio ML;Paul MJ
玉米雌性生殖组织韧皮部细胞中 T6P 的减少导致初级和次级代谢的相反变化，以及穗轴内同化物向有利于小花的转变，同时增加光合速率。转基因玉米（Zea mays）表达水稻（Oryza sativa）来自水稻 MADS6 启动子的磷酸海藻糖磷酸酶 1 (TPP1)，该启动子在开花期活跃，产量高于野生型。无论开花期间有或没有干旱条件，这种产量增加都会发生。为了了解产量增加的机制基础，我们描述了在干旱和无干旱的花期期间叶片和发育中的雌性生殖组织（包括小花、节、髓和柄）的基因表达和代谢谱。 MADS6 启动子在脉管系统中最活跃，特别是小花和髓中的韧皮部伴细胞，这与髓和小花中发现的海藻糖 6-磷酸 (T6P) 水平最大下降（2 至 3 倍）一致。低 T6P 导致初级代谢基因表达减少，次级代谢基因表达增加，特别是脂质相关途径。尽管基因表达发生类似的变化，髓和小花表现出相反的同化特征：小花中的糖、磷酸糖、氨基酸和脂质增加，但髓中减少。转基因植物中发现七个 SWEET 基因上调，这可能解释了这种同化分布。 SnRK1 活性和 SnRK1 β 亚基基因的表达、SnRK1 标记基因的表达和内源海藻糖途径基因也发生了改变。此外，与野生型玉米相比，转基因玉米的叶子在较长时间内保持较高的光合速率。总之，我们发现生殖组织中 T6P 的减少会下调初级代谢并上调次级代谢，从而导致组成组织中不同的代谢谱。我们的数据表明 T6P/ SnRK1 是全株资源分配的主要调节因子，以提高作物产量。
Decreased T6P in phloem cells of maize female reproductive tissue causes opposing changes in primary and secondary metabolism and a shift in assimilates within cobs in favor of florets, simultaneously increasing photosynthetic rate. Transgenic maize (Zea mays) that expresses rice (Oryza sativa) TREHALOSE PHOSPHATE PHOSPHATASE1 (TPP1) from the rice MADS6 promoter, which is active over the flowering period, produces higher yields than wild type. This yield increase occurs with or without drought conditions during flowering. To understand the mechanistic basis of the increased yield, we characterized gene expression and metabolite profiles in leaves and developing female reproductive tissue, comprising florets, node, pith, and shank, over the flowering period with and without drought. The MADS6 promoter was most active in the vasculature, particularly phloem companion cells in florets and pith, consistent with the largest decreases in trehalose 6-phosphate (T6P) levels (2- to 3-fold) being found in pith and florets. Low T6P led to decreased gene expression for primary metabolism and increased gene expression for secondary metabolism, particularly lipid-related pathways. Despite similar changes in gene expression, the pith and floret displayed opposing assimilate profiles: sugars, sugar phosphates, amino acids, and lipids increased in florets, but decreased in pith. Possibly explaining this assimilate distribution, seven SWEET genes were found to be up-regulated in the transgenic plants. SnRK1 activity and the expression of the gene for the SnRK1 beta subunit, expression of SnRK1 marker genes, and endogenous trehalose pathway genes were also altered. Furthermore, leaves of the transgenic maize maintained a higher photosynthetic rate for a longer period compared to wild type. In conclusion, we found that decreasing T6P in reproductive tissues down-regulates primary metabolism and up-regulates secondary metabolism, resulting in different metabolite profiles in component tissues. Our data implicate T6P/ SnRK1 as a major regulator of whole-plant resource allocation for crop yield improvement.
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影响因子：
7.4
作者：
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通讯作者：
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影响因子：
6.9
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6.9
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McLaughlin, John E.