Genome-wide transcriptomic analysis uncovers the molecular basis underlying early flowering and apetalous characteristic in Brassica napus L

Abstract

Floral transition and petal onset, as two main aspects of flower development, are crucial to rapeseed evolutionary success and yield formation. Currently, very little is known regarding the genetic architecture that regulates flowering time and petal morphogenesis in Brassica napus. In the present study, a genome-wide transcriptomic analysis was performed with an absolutely apetalous and early flowering line, APL01, and a normally petalled line, PL01, using high-throughput RNA sequencing. In total, 13,205 differential expressed genes were detected, of which 6111 genes were significantly down-regulated, while 7094 genes were significantly up-regulated in the young inflorescences of APL01 compared with PL01. The expression levels of a vast number of genes involved in protein biosynthesis were altered in response to the early flowering and apetalous character. Based on the putative rapeseed flowering genes, an early flowering network, mainly comprised of vernalization and photoperiod pathways, was built. Additionally, 36 putative upstream genes possibly governing the apetalous character of line APL01 were identified, and six genes potentially regulating petal origination were obtained by combining with three petal-related quantitative trait loci. These findings will facilitate understanding of the molecular mechanisms underlying floral transition and petal initiation in B. napus.

Transcriptomic analysis of the regulation of stalk development in flowering Chinese cabbage (Brassica campestris) by RNA sequencing

“…Plant growth and development in Brassica are complex processes that can be understood by analysing gene expression and associated regulatory mechanisms 6 , 7 , 30 . In this study, we obtained 16.3 G raw reads from three stages of stalk development by RNA-seq, of which 75.40% were mapped to the reference genome of B .…”

“…Transcriptome analysis enables the global characterization of phenotypes in organisms 27 and has been widely used to study stem and organ development, and the regulation of flowering in species such as tuberous mustard 7 , lotus ( Nelumbo nucifera ) 28 , radish ( Raphanus sativus ) 29 , and B . napus 30 . Characterizing stalk development at the molecular level can provide information that is applicable for crop improvement.…”

Fine-mapping and transcriptome analysis of a candidate gene controlling plant height in Brassica napus L.

“…The four libraries were sequenced on an Illumina HiSeq 2000 platform, and 100 bp paired-end reads were generated. These methods were described by Yu et al with modifications [64].…”

Quantitative Trait Transcripts Mapping Coupled with Expression Quantitative Trait Loci Mapping Reveal the Molecular Network Regulating the Apetalous Characteristic in Brassica napus L.

“…Thus, apetalous rapeseed is considered the ideotype of high-yield rapeseed (Mendham and Rao, 1991 ; Rao et al, 1991 ), and it has attracted the attention of botanists and breeders since its appearance. Currently, the molecular mechanism underlying the apetalous characteristic of rapeseed is poorly known because of the lack of stable apetalous mutants and the complexity of polygenic inheritance (Kelly et al, 1995 ; Fray et al, 1997 ; Wang et al, 2015 ; Yu et al, 2016 ). The apetalous characteristic of rapeseed is mainly governed by recessive genes, usually by two to four loci (Kelly et al, 1995 ), and several quantitative trait loci (QTLs) regulating petal development on chromosomes A3, A4, A5, A6, A9, C4, and C8 have been identified (Fray et al, 1997 ; Wang et al, 2015 ).…”

“…In our previous study (Wang et al, 2015 ), nine QTLs associated with petalous degree (PDgr) have been detected on chromosomes A3, A5, A6, A9, and C8 in the AH population, containing 189 recombinant inbred lines derived from a cross between an apetalous line “APL01” and a normal petalled variety “Holly.” Interestingly, three QTLs, qPD.A9-2, qPD.C8-2 , and qPD.C8-3 , are stably expressed in multiple environments (Wang et al, 2015 ). In another study (Yu et al, 2016 ), genome-wide transcriptomic analyses of the apetalous line “APL01” and another normally petalled line “PL01” both derived from the F 6 generation of crosses between apetalous “Apetalous No. 1” and normal petalous “Zhongshuang No.…”