Transcriptome analysis of Pinus massoniana Lamb. microstrobili during sexual reversal

Abstract

The normal megastrobilli and microstrobilli before and after the sexual reversal in Pinus massoniana Lamb. were studied and classified using a transcriptomic approach. In the analysis, a total of 190,023 unigenes were obtained with an average length of 595 bp. The annotated unigenes were divided into 56 functional groups and 130 metabolic pathways involved in the physiological and biochemical processes related to ribosome biogenesis, carbon metabolism, and amino acid biosynthesis. Analysis revealed 4,758 differentially expressed genes (DEGs) between the mega- and microstrobili from the polycone twig. The DEGs between the mega- and microstrobili from the normal twig were 5,550. In the polycone twig, 1,188 DEGs were identified between the microstrobili and the sexually reversed megastrobili. Concerning plant hormone signal transduction pathways, the DEGs from both the normal and polycone twigs displayed distinct male or female associated expression patterns. There were 36 common hormone-related DEGs from the two types of twigs of P. massoniana. Interestingly, expression of these DEGs was up-regulated in the bisexual strobili, which underwent the sexual reversal. A portion of MADS-box genes in the bisexual strobili were up-regulated relative to expression in microstrobili.

Reciprocal expression of MADS-box genes and DNA methylation reconfiguration initiate bisexual cones in spruce

“…10h), emphasizing auxin's role in promoting female reproductive structures and bisexual cone initiation. Similar upregulation of indole-3-acetic acid (IAA)-related genes was observed in bisexual cones of P. massoniana 20 . The important role of auxin in initiating bisexual cones may lie in its ability to mediate cell fate reprogramming in diverse pathways, including biosynthesis, polar transport, and signal transduction [69][70][71] .…”

“…Recently, the molecular mechanisms of the initiation of bisexual cones (upper ovules, basal pollen sacs) in gymnosperms have attracted increasing attention 19,20 . Although exceedingly rare in nature 21,22 , bisexual cones have been documented in different lineages of gymnosperms, particularly in conifers like Agathis, Larix, Picea, Pinus, Phyllocladus, and Saxegothaea [22][23][24][25][26][27] , suggesting that the bisexual structure likely originated from the common ancestor of gymnosperms and angiosperms 23 .…”

“…According to their study, the transcriptomes of male structures are more similar to those of female cones, indicating a "mostly female" gene expression profile in bisexual cones. In addition, Feng et al 20 revealed that hormonal regulation could be related to the sexual reversal of bisexual cones in Pinus massoniana. However, none of these studies conducted separate RNA-seq analysis on the female and male structures of bisexual cones, hindering comparative analysis of gene expression patterns between these structures.…”

Transcriptomic Analysis of Hormone Signal Transduction, Carbohydrate Metabolism, Heat Shock Proteins, and SCF Complexes before and after Fertilization of Korean Pine Ovules

“…During fertilization and early embryonic development, female gametocytes exist as multimeric structures [ 9 ], and all multimers are attached to microtubules (MTs) [ 10 ]. The phenomenon of sex reversal has also been observed in Chinese pine and Masson pine ( Pinus massoniana ), and the differentially expressed genes (DEGs) between normal branches and polycone branches were significantly up-regulated in sex-reversed polycone branches [ 11 ]. These studies shed light on the problems of the reproductive biology of Korean pine, including ovule abortion and poor fertilization.…”

Transcriptional Regulation of Pine Male and Female Cone Initiation and Development: Key Players Identified Through Comparative Transcriptomics

“…So far, orthologs of B, C/D and E-class floral homeotic genes and known to be involved in the control of meristem formation and organ identity have been identified in gymnosperms (Tandre et al, 1995(Tandre et al, , 1998Mouradov et al, 1998;Rutledge et al, 1998;Sundström and Engström, 2002;Gramzow and Theissen, 2010;Melzer et al, 2010;Uddenberg et al, 2013;Gramzow et al, 2014;Silva et al, 2016;Chen et al, 2017). Other studies focusing on naturally occurring rare mutants such as early-cone setting or bisexual cone phenotypes, or using hormonal treatments to study genes expressed during reproductive structure development led to the identification of conifer-specific MADS-box genes such as the DEFICIENS-AGAMOUS-LIKE (DAL) genes (Niu et al, 2015;Zhao et al, 2015;Feng et al, 2018).…”