Fine Mapping and Transcriptome Analysis of Virescent Leaf Gene v-2 in Cucumber (Cucumis sativus L.)

Abstract

Leaf color mutants are the ideal materials to explore the pathways of chlorophyll metabolism, chloroplast development and photosynthesis system. In this study, a new virescent leaf mutant 104Y was identified by spontaneous mutation, whose cotyledon and upper five true leaves were yellow color. The yellow true leaves gradually turned green from top to bottom with increased chlorophyll contents. Genetic analysis indicated that the virescent leaf was controlled by one single recessive gene v-2, which was accurately mapped into 36.0-39.7 Mb interval on chromosome 3 by using BSA-seq and linkage analysis. Fine mapping analysis further narrowed v-2 into 73-kb genomic region including eight genes with BC 1 and F 2 populations. Through BSA-seq and cDNA sequencing analysis, only one nonsynonymous mutation existed in the Csa3G890020 gene encoding auxin F-box protein was identified, which was predicted as the candidate gene controlling virescent leaf. Comparative transcriptome analysis and quantitative real-time PCR analysis revealed that the expression level of Csa3G890020 was not changed between EC1 and 104Y. However, RNA-seq analysis identified that the key genes involved in chlorophyll biosynthesis and auxin signaling transduction network were mainly down-regulated in 104Y compared with EC1, which indicated that the regulatory functions of Csa3G890020 could be performed at post-transcriptional level rather than transcriptional level. This is the first report to map-based clone an auxin F-box protein gene related to virescent leaf in cucumber. The results will exhibit a new insight into the chlorophyll biosynthesis regulated by auxin signaling transduction network.

Identification and function analysis of yellow-leaf mutant (YX-yl) of broomcorn millet

“…Our results revealed that the leaves of the YX-yl mutant exhibited much lower chlorophyll content, especially Chl b content, compared with the wild type, which played an important role in harvesting light and energy conversion. We hypothesized that the yellow phenotype of YX-yl leaves is caused by a deficiency in chlorophyll content, especially Chl b content, which has also been reported in cabbage [ 2 ], wheat [ 7 ], rice [ 6 ], cucumber [ 13 ], foxtail millet [ 8 ], and Arabidopsis [ 9 ].…”

“…The photosynthetic rate and chloroplast ultrastructure are directly affected by leaf color mutations [ 4 , 8 , 13 , 14 , 41 ]. In a leaf-color mutant of rice, the chloroplasts are degrade, the matrix is disordered, and the thylakoids almost completely disappear [ 4 ].…”

Genome-Wide Identification, Phylogenetic and Expression Pattern Analysis of GATA Family Genes in Cucumber (Cucumis sativus L.)

“…The expression data of cucumber GATA genes between the first true leaves of green and virescent plant were obtained from our previous study (PRJNA612596) [59]. The expression data of cucumber GATA genes in different tissue (PRJNA80169) [60] and different biotic stresses including downy mildew resistance (PRJNA285071) [61], powdery mildew resistance (PRJNA321023) [62], root-knot nematode resistance (PRJNA419665) [63] were all obtained from Cucurbit Genomics Database (CuGenDB) (http://cucurbitgenomics.…”

Integrating physiology, genetics, and transcriptome to decipher a new thermo-sensitive and light-sensitive virescent leaf gene mutant in cucumber

“…Cucumber has many leaf color mutants, including chlorophyll deficient (cd) , light-sensitive (ls) , pale lethal (pl) , golden leaf (g) , golden cotyledon (gc) , yellow cotyledons-1 (yc-1) , yellow cotyledons-2 (yc-2) , yellow plant (yp) , yellow stem (ys) , light green cotyledons-1 (lg-1) , light green cotyledons-2 (lg-2) , virescent (v) , and variegated virescent ( vvi ; Pierce and Wehner, 1990 ). Others include virescent-1 ( v-1 ; Miao et al, 2016 ), virescent-yellow leaf ( vyl ; Song et al, 2018 ), variegated leaf ( vl ; Cao et al, 2018 ), yellow-green leaf ( yg1 ; Ding et al, 2019 ), virescent-2 ( v-2 ; Zhang et al, 2020 ), yellow young leaf-1 ( yyl-1 ; Hu et al, 2020 ), yellow leaf 2.1 ( yl2.1 ; Xiong et al, 2020 ), and albino ( Yan et al, 2020 ).…”

“…In addition, the spontaneous mutant yg1 with yellow-green leaves is probably caused by mutations in the tandem 13-lipoxygnease (LOX) genes ( Ding et al, 2019 ). The virescent leaf spontaneous mutant v-2 could possibly be caused by a mutation in Csa3G890020 , which encodes the auxin F-box protein ( Zhang et al, 2020 ). An EMS mutagenesis in the CsHD that contains the HD (histidine and aspartate) structural domain proteins synthesizes the yellow leaf mutant, yyl-1 .…”