Natural variation in the fast phase of chlorophyll a fluorescence induction curve (OJIP) in a global rice minicore panel
Natural variation in the fast phase of chlorophyll a fluorescence induction curve (OJIP) in a global rice minicore panel
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DOI：
10.1007/s11120-020-00794-z
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发表时间：
2020-11-07
影响因子：
3.7
通讯作者：
Zhu, Xin-Guang
中科院分区：
文献类型：
--
作者：
Khan, Naveed;Essemine, Jemaa;Zhu, Xin-Guang
光合作用可以通过叶绿素a荧光诱导（FI）来探测，它提供了对光系统II中电子转移过程的详细了解。本文系统地研究了水稻FI的快速期，即OJIP期的自然变异。叶绿素a荧光诱导曲线的OJIP阶段被称为持续不到一秒的“快速瞬态”;它是在暗适应样品暴露于饱和光后获得的。在OJIP曲线中，“0”代表“原点”（最小荧光），“P”代表“峰值”（最大荧光），J和I代表0和P水平之间的拐点。此外，F-o是“0”能级处的荧光强度，而F-m是P能级处的强度，并且F-v（= F-m - F-o）是可变荧光。我们调查了199份水稻材料在田间条件（FC）和生长室条件（GC）下生长的FI曲线的一组定量参数。我们的研究结果表明，粳稻（JAP）和籼稻（IND）亚组之间的显着变化，在这两种生长条件下，在几乎所有的参数来自OJIP曲线。与IND亚群相比，JAP中的变量与最大值（F-v/F-m）和变量与最小值（F-v/F-o）荧光的比值、性能指数（PIabs）以及I-P相振幅（A（I-P））显示出更高的值。相反，O-J相的振幅（A（O-J））和OJIP曲线上方的归一化面积（S-m）显示相反的趋势。进行的遗传分析表明，GC下生长的植物似乎更受环境因素的影响比那些生长在外地。我们进一步进行了全基因组关联研究（GWAS）使用11个参数来自植物生长在外地。总共有596个非独特的显着位点的基础上，这些参数被确定的GWAS。几个光合作用相关的蛋白质被确定为与不同的OJIP参数。我们发现，具有高相关性的性状通常与相似的基因组区域相关。具体地，FI的热相，其包括OJIP曲线的J-I和I-P子相（A（J-I）和A（I-P））的幅度，又与某些共同的基因组区域相关联。我们的研究是第一个处理水稻的自然变异，目的是表征潜在的候选基因控制的幅度和半衰期的每个阶段的OJIP FI曲线。
Photosynthesis can be probed through Chlorophyll a fluorescence induction (FI), which provides detailed insight into the electron transfer process in Photosystem II, and beyond. Here, we have systematically studied the natural variation of the fast phase of the FI, i.e. the OJIP phase, in rice. The OJIP phase of the Chl a fluorescence induction curve is referred to as "fast transient" lasting for less than a second; it is obtained after a dark-adapted sample is exposed to saturating light. In the OJIP curve, "O" stands for "origin" (minimal fluorescence), "P" for "peak" (maximum fluorescence), and J and I for inflection points between the O and P levels. Further, F-o is the fluorescence intensity at the "O" level, whereas F-m is the intensity at the P level, and F-v (= F-m - F-o) is the variable fluorescence. We surveyed a set of quantitative parameters derived from the FI curves of 199 rice accessions, grown under both field condition (FC) and growth room condition (GC). Our results show a significant variation between Japonica (JAP) and Indica (IND) subgroups, under both the growth conditions, in almost all the parameters derived from the OJIP curves. The ratio of the variable to the maximum (F-v/F-m) and of the variable to the minimum (F-v/F-o) fluorescence, the performance index (PIabs), as well as the amplitude of the I-P phase (A(I-P)) show higher values in JAP compared to that in the IND subpopulation. In contrast, the amplitude of the O-J phase (A(O-J)) and the normalized area above the OJIP curve (S-m) show an opposite trend. The performed genetic analysis shows that plants grown under GC appear much more affected by environmental factors than those grown in the field. We further conducted a genome-wide association study (GWAS) using 11 parameters derived from plants grown in the field. In total, 596 non-unique significant loci based on these parameters were identified by GWAS. Several photosynthesis-related proteins were identified to be associated with different OJIP parameters. We found that traits with high correlation are usually associated with similar genomic regions. Specifically, the thermal phase of FI, which includes the amplitudes of the J-I and I-P subphases (A(J-I) and A(I-P)) of the OJIP curve, is, in turn, associated with certain common genomic regions. Our study is the first one dealing with the natural variations in rice, with the aim to characterize potential candidate genes controlling the magnitude and half-time of each of the phases in the OJIP FI curve.