Fine mapping and photosynthetic characteristics of the lower chlorophyll b 1 mutant in rice (Oryza sativa L.)

Abstract

Chlorophylls absorb and transfer light energy to the photosynthetic system. Consequently, chlorophyll content is strongly related to crop biomass and yield. We isolated a rice spontaneous mutant, lower chlorophyll b 1 (lcb1), from a recombinant inbred line population. Under normal growth conditions, lcb1 plants produced yellow leaves with decreased total chlorophyll and chlorophyll b contents, but normal chlorophyll a content. Photosynthetic and fluorescence parameters differed between wild-type and lcb1 plants. Compared with wild type, lcb1 had a higher electron transfer rate, a lower photochemical quenching coefficient and significantly reduced grain number, biomass and yield. A recessive nuclear gene controlled the mutant trait. Through map-based cloning, we located the LCB1 gene in a 117.4-kb region on the short arm of chromosome 3, close to the centromere, in a region containing 15 predicted candidate genes. None of these genes was directly related to chlorophylls or the chloroplast; therefore, lcb1 may be a mutation of a novel gene. These results will be useful for further research on the molecular mechanisms controlling biogenesis and chloroplast biochemical processes.

Physiological and Transcriptome Analysis of a Yellow-Green Leaf Mutant in Birch (Betula platyphylla × B. Pendula)

“…Leaf color variation is one of the most common mutated traits as it is easily discovered in higher plants. Up to now, many Chl-deficient mutants have been identified in herbaceous and woody plants, including Arabidopsis [9], rice [10], maize [11], wheat (Triticum aestivum L.) [12], cotton (Gossypium barbadense L.) [13], and tea (Camellia sinensis (L.) O. Kuntze) [14]. It has been reported that a yellow-green leaf mutant (siygl1) of foxtail millet (Setaria italic L.) isolated following ethyl methanesulfonate (EMS) treatment was due to the loss function of the SiYGL1 gene.…”

Genome-wide association mapping of quantitative trait loci for chalkiness-related traits in rice (Oryza sativa L.)

“…The OsFMO(t) gene located on chromosome 3 regulates IAA biosynthesis possibly locally and plays an important role in the formation of local IAA concentrations that are critical for regulating normal growth and development in rice ( Yi et al, 2013 ). The OsFMO1 gene located on chromosome 9 can affect auxin synthesis, signal transduction, polar transport, and growth and development in plants ( Liu et al, 2019 ). Grain filling is an important physiological process in rice growth; therefore, we hypothesize that LOC_Os11g10170 encoding flavin monooxygenase may inhibit or accelerate the transport of photosynthetic products through the phloem to the endosperm cells in the form of sucrose during grain filling to affect starch synthesis, resulting in different degrees of chalkiness among the accessions.…”

Identification of candidate genes and clarification of the maintenance of the green pericarp of weedy rice grains

“…The expression of the ethylene-responsive genes Sub1A and Sub1C is reportedly up-regulated during Chl degradation in leaves (Fukao et al, 2006). The Chl degradation and biosynthesis pathways in rice leaves have been characterized (Sato et al, 2009;Liu et al, 2015;Nguyen et al, 2020). More specifically, Chl degradation is catalyzed by several catabolic enzymes.…”