Kumar Awadhesh, Panda Darshan, Mohanty Soumya, Biswal Monalisha, Dey Prajjal, Dash Manaswini, Sah Rameswar Prasad, Kumar Sudhir, Baig Mirza Jaynul, Behera Lambodar
ICAR-National Rice Research Institute, Cuttack, Odisha 753006 India.
Faculty of Agriculture, Sri Sri University, Cuttack, Odisha 754006 India.
Physiol Mol Biol Plants. 2020 Dec;26(12):2465-2485. doi: 10.1007/s12298-020-00905-z. Epub 2020 Dec 19.
Rice grain yield is drastically reduced under low light especially in (wet) season due to cloudy weather during most part of crop growth. Therefore, 50-60% of yield penalty was observed. To overcome this problem, identification of low light tolerant rice genotypes with a high buffering capacity trait such as photosynthetic rate has to be developed. Sedoheptulose-1,7 bisphosphatase, a light-regulated enzyme, plays pivotal role in the Calvin cycle by regenerating the substrate (RuBP) for RuBisCo and therefore, indirectly regulates the influx of CO for this crucial process. We found a potential role of SBPase expression and activity in low light tolerant and susceptible rice genotypes by analyzing its influence on net photosynthetic rate and biomass. We observed a significant relationship of yield with photosynthesis, SBPase expression and activity especially under low light conditions. Two tolerant and two susceptible rice genotypes were used for the present study. Tolerant genotypes exhibited significant but least reduction compared to susceptible genotypes in the expression and activity of SBPase, which was also manifested in its photosynthetic rate and finally in the grain yield under low light. However, susceptible genotypes showed significant reduction in SBPase activity along with photosynthesis and grain yield suggesting that tracking the expression and activity of SBPase could form a simple and reliable method to identify the low light tolerant rice cultivars. The data were analyzed using the Indostat 7.5, Tukey-Kramer method through Microsoft Excel 2019 and PAST4.0 software. The significant association of SBPase activity with the grain yield, net assimilation rate, electron transfer rate, biomass and grain weight were observed under low light stress. These traits should be considered while selecting and breeding for low light tolerant cultivars. Thus, SBPase plays a major role in the low light tolerance mechanism in rice.
在弱光条件下，尤其是在（湿润）季节，由于作物生长大部分时间天气多云，水稻产量会大幅降低。因此，观察到产量损失达50%-60%。为克服这一问题，必须培育出具有高缓冲能力性状（如光合速率）的耐弱光水稻基因型。景天庚酮糖-1,7-二磷酸酶是一种光调节酶，通过为核酮糖-1,5-二磷酸羧化酶/加氧酶（RuBisCo）再生底物（核酮糖-1,5-二磷酸，RuBP）在卡尔文循环中起关键作用，因此间接调节这一关键过程中二氧化碳的流入。通过分析景天庚酮糖-1,7-二磷酸酶（SBPase）对净光合速率和生物量的影响，我们发现了其在耐弱光和敏感水稻基因型中的潜在作用。我们观察到，尤其是在弱光条件下，产量与光合作用、SBPase表达及活性之间存在显著关系。本研究使用了两个耐弱光和两个敏感水稻基因型。与敏感基因型相比，耐弱光基因型在SBPase表达和活性方面表现出显著但最小程度的降低，这也体现在其光合速率上，最终体现在弱光条件下的籽粒产量上。然而，敏感基因型的SBPase活性以及光合作用和籽粒产量均显著降低，这表明追踪SBPase的表达和活性可形成一种简单可靠的方法来鉴定耐弱光水稻品种。使用Indostat 7.5软件、通过Microsoft Excel 2019中的Tukey-Kramer方法以及PAST4.0软件对数据进行了分析。在弱光胁迫下，观察到SBPase活性与籽粒产量、净同化率、电子传递速率、生物量和粒重之间存在显著关联。在选择和培育耐弱光品种时应考虑这些性状。因此，SBPase在水稻耐弱光机制中起主要作用。
