Conjunctive Analyses of BSA-Seq and BSR-Seq to Reveal the Molecular Pathway of Leafy Head Formation in Chinese Cabbage.

Rui Li,Zhongle Hou,Liwei Gao,Xilin Hou,Changwei Zhang,Dong Xiao,Lixiao Song,Jiyong Yan

doi:10.3390/plants8120603

Abstract

As the storage organ of Chinese cabbage, the leafy head was harvested as a commercial product due to its edible value. In this study, the bulked segregant analysis (BSA) and bulked segregant RNA-Seq (BSR) were performed with F2 separation progeny to study the molecular mechanism of leafy head formation in Chinese cabbage. BSA-Seq analysis located four candidate regions containing 40 candidate genes, while BSR-Seq analysis revealed eight candidate regions containing 607 candidate genes. The conjunctive analyses of these two methods identified that Casein kinase gene BrCKL8 (Bra035974) is the common candidate gene related with leafy head formation in Chinese cabbage, and it showed high expression levels at the three segments of heading type plant leaves. The differentially expressed genes (DEGs) between two set pairs of cDNA sequencing bulks were divided into two categories: one category was related with five hormone pathways (Auxin, Ethylene, Abscisic acid, Jasmonic acid and Gibberellin), the other category was composed of genes that associate with the calcium signaling pathway. Moreover, a series of upregulated transcriptional factors (TFs) were also identified by the association analysis of BSR-Seq analysis. The leafy head development was regulated by various biological processes and effected by diverse external environment factors, so our research will contribute to the breeding of perfect leaf-heading types of Chinese cabbage.

Highlights

Chinese cabbage (Brassica rapa ssp. pekinensis) originates in China, is one of the widely cultivated horticultural crops in Asia [1]
For rapidly investigating the genetic control of agronomic traits, bulked segregant analysis (BSA) and bulked segregant RNA-Seq (BSR) were developed, which just need the construction of a segregating population [20,21]
The conjunctive analyses of BSA-Seq and bulked segregant RNA-seq (BSR-Seq) was performed with the F2 separation progeny to study the molecular mechanism of leafy head formation in genetic and transcriptional level

Summary

Introduction

Chinese cabbage (Brassica rapa ssp. pekinensis) originates in China, is one of the widely cultivated horticultural crops in Asia [1]. Pekinensis) originates in China, is one of the widely cultivated horticultural crops in Asia [1]. The vegetative growth of Chinese cabbage is divided into four growth stages, i.e., seeding, rosette, folding and heading stages [2]. The newly formed leaves begin to bold and curl inward at the top, which are essential for tight leafy head formation. Leafy head tightness and size are important indices to assessing the economic value of Chinese cabbage [3]. The molecular mechanism of leafy head formation in Chinese cabbage remains elusive. The leafy head development of Chinese cabbage is affected by diversity factors, such as phytohormones’

Methods

Results

Conclusion