Characterization and Transcriptomic Analysis of a Novel Yellow-Green Leaf Wucai (Brassica Campestris L.) Germplasm

Abstract

Background: Leaf color mutants are the ideal materials to explore the pathways of chlorophyll (Chl) metabolism, chloroplast development, and photosynthesis system. In this study, a spontaneous yellow-green leaf wucai (Brassica campestris L.) mutant “WY16-13” was identified, which exhibited yellow-green leaf color during its entire growth period. However, current understanding of the molecular mechanism underlying Chl metabolism and chloroplast development of “WY16-13” is limited.Results: Comparative transcriptome profiling was performed using leaves from the yellow-green leaf type (WY16-13) and normal green-leaf type (W16-13). A total of 54.12 million (M) (WY16-13) and 56.17 M (W16-13) reads were generated. A total of 40,578 genes were identified from the mapped libraries. We identified 3,882 differentially expressed genes (DEGs) in WY16-13 compared with wild-type W16-13 (i.e., 1,603 upregulated genes and 2,279 downregulated genes). According to the Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, these DEGs are involved in porphyrin and Chl metabolism [i.e., chlorophyllase (CLH), heme oxygenase (HO), chlorophyll(ide) b reductase (NYC), and protochlorophyllide oxidoreductase (POR) genes], carbohydrate metabolism, photosynthesis, and carbon fixation in photosynthetic organisms. Moreover, deficiency in Chl biosynthetic intermediates in the mutant revealed that the formation of the yellowing phenotype was related to the disorder of heme metabolism.Conclusions: Our results provide valuable insights into Chl deficiency in the yellow-green leaf mutant and a bioinformatics resource for further functional identification of key allelic genes responsible for differences in Chl content.

Functional analysis of CqPORB in the regulation of chlorophyll biosynthesis in Chenopodium quinoa

“…In addition to Arabidopsis and rice, the function of POR genes has also been characterized in many other plant species, including barley (Hordeum vulgare L.) (Holtorf et al, 1995), wheat (Triticum aestivum) (Teakle and Griffiths, 1993), maize (Zea mays) (Selstam et al, 2002), tobacco (Nicotiana tabacum L.) (Selstam et al, 2002), and cabbage (Brassica oleracea cv. Capitata) (Nie et al, 2021).…”