Comparative Transcriptome Analysis Reveals Key Genes and Pathways Involved in Prickle Development in Eggplant

Abstract

Eggplant is one of the most important vegetables worldwide. Prickles on the leaves, stems and fruit calyxes of eggplant may cause difficulties during cultivation, harvesting and transportation, and therefore is an undesirable agronomic trait. However, limited knowledge about molecular mechanisms of prickle morphogenesis has hindered the genetic improvement of eggplant. In this study, we performed the phenotypic characterization and transcriptome analysis on prickly and prickleless eggplant genotypes to understand prickle development at the morphological and molecular levels. Morphological analysis revealed that eggplant prickles were multicellular, lignified and layered organs. Comparative transcriptome analysis identified key pathways and hub genes involved in the cell cycle as well as flavonoid biosynthetic, photosynthetic, and hormone metabolic processes during prickle development. Interestingly, genes associated with flavonoid biosynthesis were up-regulated in developing prickles, and genes associated with photosynthesis were down-regulated in developing and matured prickles. It was also noteworthy that several development-related transcription factors such as bHLH, C2H2, MYB, TCP and WRKY were specifically down- or up-regulated in developing prickles. Furthermore, four genes were found to be differentially expressed within the Pl locus interval. This study provides new insights into the regulatory molecular mechanisms underlying prickle morphogenesis in eggplant, and the genes identified might be exploited in breeding programs to develop prickleless eggplant cultivars.

Evaluation of Advanced Backcrosses of Eggplant with Solanum elaeagnifolium Introgressions under Low N Conditions

“…For the three traits related to the presence of prickles (P-StPrick, F-LeafPrick, and F-CalPrick) we detected three QTLs (ps6, pl6, and pc6, respectively) located at the same position on chromosome 6, indicating a common genetic basis for these three traits. Previously, QTLs related to prickliness were mapped in chromosome 6 [80] in an S. linnaeanum × S. melongena F2 population [76,81], in a BC1 population of the ILs of S. incanum × S. melongena [82], in an F2 intraspecific population [83], and in a panel of 191 accessions of breeding lines, old varieties, and landrace selections of eggplant [77], supporting that a major gene conserved in the eggplant group is present in this region [84,85]. For fruit traits, a QTL was detected for fruit width (F-Width) on chromosome 7 (fw7).…”

Improved genome assembly and pan‐genome provide key insights into eggplant domestication and breeding

“…It is thought that plant prickles are modified glandular trichomes and that their biogenesis in controlled by transcription factors from the MYB, bHLH, WD40, WRKY, and C2H2 zinc finger families (Wang et al ., 2019 ). Indeed, by comparing prickled and non‐prickled genotypes, we identified several SSs containing genes encoding homologs of Arabidopsis transcription factors involved in trichome initiation, such as GL1 and GIS2 (Wang et al ., 2019 ; Zhang et al ., 2021 ). SSs on chr.…”

“…SSs on chr. 6 fall in proximity of previously identified QTLs and QTNs as well as the morphological marker PRICKLINESS (Frary et al ., 2014 ; Gramazio et al ., 2014 ; Portis et al ., 2015 ) and the recently identified Pl locus involved in prickle formation in eggplant (Miyatake et al ., 2020 ; Zhang et al ., 2021 ), suggesting that these regions have been the targets of human selection for presence/absence of prickles.…”

Identification of Quantitative Trait Loci Controlling the Development of Prickles in Eggplant by Genome Re-sequencing Analysis

“…In horticultural crops, some HD-ZIP proteins were also identified to participate in the development regulation of multicellular trichomes, such as Glabrous 1 (CsGL1), Micro-trichome (Mict), TRICHOME-LESS/Glabrous 3 (TRIL/CsGL3) and Cucumis sativus TRANSPARENT TESTA GLABRA1 (CsTTG1) in C. sativus (cucumber) and CsWUS in citrus (Zhao et al, 2015 ; Cui et al, 2016 ; Liu et al, 2016 ; Chen et al, 2017 ; Zhang et al, 2020a ). Several development-related transcription factors such as bHLH, C2H2, MYB, TCP, and WRKY, which were specifically downregulated or upregulated in developing prickles, were also found in eggplant (Zhang et al, 2021 ).…”