Suppression of chloroplast triose phosphate isomerase evokes inorganic phosphate-limited photosynthesis in rice
Suppression of chloroplast triose phosphate isomerase evokes inorganic phosphate-limited photosynthesis in rice
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水稻叶绿体磷酸丙糖异构酶的抑制引起无机磷酸盐限制的光合作用
DOI：
10.1093/plphys/kiab576
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发表时间：
2021
期刊：
影响因子：
7.4
通讯作者：
Makino Amane
中科院分区：
文献类型：
--
作者：
Suzuki Yuji;Ishiyama Keiki;Yoon Dong-Kyung;Takegahara-Tamakawa Yuki;Kondo Eri;Suganami Mao;Wada Shinya;Miyake Chikahiro;Makino Amane
当通过蔗糖或淀粉合成的无机磷酸盐受到限制时，用于ATP合成的无机磷酸盐（Pi）的可用性被认为限制了[CO2]升高时的光合作用。本文报道了叶绿体磷酸三糖异构酶（cpTPI）容量不足导致pi限制光合作用发生的另一种机制。cpTPI-反义转基因水稻（Oryza sativa）植株在cpTPI含量降低55% ~ 86%的情况下，CO2敏感性对CO2同化速率(A)的影响降低，甚至在CO2升高[CO2]时发生逆转。[CO2]升高时，从戊糖磷酸盐到3-磷酸甘油酸的Calvin-Benson循环代谢物的池大小增加，而ATP的池大小减少。这些现象与pi限制光合作用的典型症状相似，说明需要足够的cpTPI容量来防止pi限制光合作用的发生，cpTPI含量适度影响[CO2]升高时的光合能力。由于不同基因型的叶片总氮含量有轻微的差异，因此在以单位叶片总氮（A/N和cpTPI/N）表达这些参数后，研究了A与cpTPI含量之间的关系。CO2升高条件下，A/N随着cpTPI/N的降低呈线性下降，然后由于cpTPI/N的进一步降低，A/N急剧下降。在这个线性范围内，cpTPI/N降低80%导致升高[CO2]的inA/N降低高达27%。因此，cpTPI功能对高[CO2]下的光合作用至关重要。
The availability of inorganic phosphate (Pi) for ATP synthesis is thought to limit photosynthesis at elevated [CO2] when Piregeneration via sucrose or starch synthesis is limited. We report here another mechanism for the occurrence of Pi-limited photosynthesis caused by insufficient capacity of chloroplast triose phosphate isomerase (cpTPI). IncpTPI-antisense transgenic rice (Oryza sativa) plants with 55%–86% reductions in cpTPI content, CO2sensitivity of the rate of CO2assimilation (A) decreased and even reversed at elevated [CO2]. The pool sizes of the Calvin–Benson cycle metabolites from pentose phosphates to 3-phosphoglycerate increased at elevated [CO2], whereas those of ATP decreased. These phenomena are similar to the typical symptoms of Pi-limited photosynthesis, suggesting sufficient capacity of cpTPI is necessary to prevent the occurrence of Pi-limited photosynthesis and that cpTPI content moderately affects photosynthetic capacity at elevated [CO2]. As there tended to be slight variations in the amounts of total leaf-N depending on the genotypes, relationships betweenAand the amounts of cpTPI were examined after these parameters were expressed per unit amount of total leaf-N (A/N and cpTPI/N, respectively).A/N at elevated [CO2] decreased linearly as cpTPI/N decreased beforeA/N sharply decreased, owing to further decreases in cpTPI/N. Within this linear range, decreases in cpTPI/N by 80% led to decreases up to 27% inA/N at elevated [CO2]. Thus, cpTPI function is crucial for photosynthesis at elevated [CO2].