PDF(Pubmed)
Abstract：
Low phosphate (Pi) availability decreases photosynthesis, with phosphate limitation of photosynthesis occurring particularly during grain filling of cereal crops; however, effective genetic solutions remain to be established. We previously discovered that rice phosphate transporter OsPHO1;2 controls seed (sink) development through Pi reallocation during grain filling. Here, we find that OsPHO1;2 regulates Pi homeostasis and thus photosynthesis in leaves (source). Loss-of-function of OsPHO1;2 decreased Pi levels in leaves, leading to decreased photosynthetic electron transport activity, CO2 assimilation rate, and early occurrence of phosphate-limited photosynthesis. Interestingly, ectopic expression of OsPHO1;2 greatly increased Pi availability, and thereby, increased photosynthetic rate in leaves during grain filling, contributing to increased yield. This was supported by the effect of foliar Pi application. Moreover, analysis of core rice germplasm resources revealed that higher OsPHO1;2 expression was associated with enhanced photosynthesis and yield potential compared to those with lower expression. These findings reveal that phosphate-limitation of photosynthesis can be relieved via a genetic approach, and the OsPHO1;2 gene can be employed to reinforce crop breeding strategies for achieving higher photosynthetic efficiency.
摘要：
低磷酸盐（Pi）可用性降低光合作用，特别是在谷类作物的籽粒灌浆过程中发生的光合作用的磷酸盐限制；然而，有效的遗传解决方案仍有待建立。我们先前发现水稻磷酸盐转运蛋白OsPHO1;2通过籽粒灌浆过程中的Pi重新分配来控制种子（库）发育。这里,我们发现OsPHO1;2调节Pi稳态，从而调节叶片中的光合作用（来源）。OsPHO1的功能丧失；2降低了叶片中的Pi水平，导致光合电子传递活性下降，CO2同化率，和早期发生磷酸盐限制的光合作用。有趣的是,OsPHO1的异位表达；2大大提高了Pi的可用性，因此，籽粒灌浆过程中叶片光合速率增加，有助于提高产量。叶面Pi施用的效果支持了这一点。此外，对核心水稻种质资源的分析表明，较高的OsPHO1;2表达与较低表达的人相比，与增强的光合作用和产量潜力有关。这些发现表明，光合作用的磷酸盐限制可以通过遗传方法来缓解，和OsPHO1;2基因可用于加强作物育种策略，以实现更高的光合效率。
