Primary leaf‐type ferredoxin 1 participates in photosynthetic electron transport and carbon assimilation in rice

Abstract

Ferredoxins (Fds) play a crucial role in photosynthesis by regulating the distribution of electrons to downstream enzymes. Multiple Fd genes have been annotated in the Oryza sativa L. (rice) genome; however, their specific functions are not well understood. Here, we report the functional characterization of rice Fd1. Sequence alignment, phylogenetic analysis of seven rice Fd proteins and quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that rice Fd1 is a primary leaf-type Fd. Electron transfer assays involving NADP + and cytochrome c indicated that Fd1 can donate electrons from photosystem I (PSI) to ferredoxin-NADP + reductase. Loss-of-function fd1 mutants showed chlorosis and seedling lethality at the three-leaf stage. The deficiency of Fd1 impaired photosynthetic electron transport, which affected carbon assimilation. Exogenous glucose treatment partially restored the mutant phenotype, suggesting that Fd1 plays an important role in photosynthetic electron transport in rice. In addition, the transcript levels of Fd-dependent genes were affected in fd1 mutants, and the trend was similar to that observed in fdc2 plants. Together, these results suggest that OsFd1 is the primary Fd in photosynthetic electron transport and carbon assimilation in rice.

The bundle sheath of rice is conditioned to play an active role in water transport as well as sulfur assimilation and jasmonic acid synthesis

“…Exceptions included one ferredoxin gene that showed the highest transcript abundance in bundle sheath cells, three ferredoxin genes for which transcripts were more abundant in bundle sheath and veinal cells, compared with mesophyll cells, and three homologues of photosystem I subunit PsaA and photosystem II subunit PsbK (Figure S5a, b). In contrast to the primary ferredoxin Fd1 (LOC_Os08g01380) involved in photosynthetic electron transport (He et al , 2020), and primarily expressed in mesophyll cells, four other ferredoxins including the nitrate‐inducible Fd (LOC_Os05g37140) (Doyama et al , 1998) were preferentially expressed in bundle sheath and veinal cells, indicating that rice bundle sheath cells have optimised reducing power for nitrate reduction as well as sulphur assimilation. A gradient from high expression in mesophyll cells to low expression in veinal cells was observed for most enzymes of the Calvin–Benson–Bassham cycle.…”

An Integration of MicroRNA and Transcriptome Sequencing Analysis Reveal Regulatory Roles of miRNAs in Response to Chilling Stress in Wild Rice

“…Two predicted SDETGs of osa-miR1850.1, LOC_Os03g48040 ( OsFdC2 ) and LOC_Os09g29200 , which have a similar lower expression level in 9311 in comparison with DC90, were enriched in the photosynthesis pathway (ko00195) and the glutathione metabolism pathway (ko00480), respectively. LOC_Os03g48040 , encoding a ferredoxin, affects photosynthetic competence by controlling chloroplast development and chlorophyll content in rice [ 36 , 37 ]. A lower downregulation level of this gene in 9311 under chilling stress may result in severe impairing of its chloroplast development when exposed to low temperature.…”

“…Two predicted SDETGs of osa-miR1850.1, LOC_Os03g48040 and LOC_Os09g29200 , were enriched in the photosynthesis pathway (ko00195) and glutathione metabolism pathway (ko00480), respectively. LOC_Os03g48040 encodes a ferredoxin that is involved in chloroplast development in rice [ 36 ]. In addition, two predicted SDETGs of osa-miR1846a/b-5p, LOC_Os09g27820 and LOC_Os11g48020 , were enriched in the porphyrin and chlorophyll metabolism pathway (ko00860) and steroid biosynthesis pathway (ko00100), respectively.…”

Ferredoxin 1 is downregulated by the accumulation of abscisic acid in an ABI5‐dependent manner to facilitate rice stripe virus infection in Nicotiana benthamiana and rice

“…Ferredoxins are a group of nuclear‐encoded chloroplast proteins that act as crucial determinants for receiving and distributing electrons to various downstream pathways, including assimilation of CO 2 , nitrogen and sulfur (Hanke and Mulo, 2013). Loss‐of‐function fd1 mutants of rice have chlorosis in the first leaves and seedlings die at the three‐leaf stage, indicating the indispensable role of FD1 for plant growth and development (He et al ., 2020). Recently, FDs have been receiving increasing attention for their positive roles in plant immunity against various pathogens (Lin et al ., 2010; Su et al ., 2014; Wang et al ., 2018a; Yang et al ., 2020a).…”