Insight Into the Multiple Branches Traits of a Mutant in Larix olgensis by Morphological, Cytological, and Transcriptional Analyses

Abstract

Larix olgensis is a tall deciduous tree species that has many applications in the wood fiber industry. Bud mutations are somatic mutations in plants and are considered an ideal material to identify and describe the molecular mechanism of plant mutation. However, the molecular regulatory mechanisms of bud mutations in L. olgensis remain unknown. In this study, dwarfed (or stunted), short-leaved, and multi-branched mutants of L. olgensis were found and utilized to identify crucial genes and regulatory networks controlling the multiple branch structure of L. olgensis. The physiological data showed that the branch number, bud number, fresh and dry weight, tracheid length, tracheid length-width ratio, inner tracheid diameter, and epidermal cell area of mutant plants were higher than that of wild-type plants. Hormone concentration measurements found that auxin, gibberellin, and abscisic acid in the mutant leaves were higher than that in wild-type plants. Moreover, the transcriptome sequencing of all samples using the Illumina Hiseq sequencing platform. Transcriptome analysis identified, respectively, 632, 157, and 199 differentially expressed genes (DEGs) in buds, leaves, and stems between mutant plants and wild type. DEGs were found to be involved in cell division and differentiation, shoot apical meristem activity, plant hormone biosynthesis, and sugar metabolism. Furthermore, bZIP, WRKY, and AP2/ERF family transcription factors play a role in bud formation. This study provides new insights into the molecular mechanisms of L. olgensis bud and branch formation and establishes a fundamental understanding of the breeding of new varieties in L. olgensis.

Jasmonic acid negatively regulates branch growth in pear

“…Compared with MP, OP developed more branches at an early stage and the leaf axillary buds produced spiny spur shoots. Similar results have been reported in other species, such as birch and larch ( Han et al., 2019 ; Cai et al., 2021 ). In addition, the vascular bundles and abaxial epidermal cells of MP leaves were larger than those of OP, and the areal proportion of the pith, xylem, and phloem in new shoots of MP from the base to the tip was greater than that of OP, and almost no conducting tissue had differentiated at the shoot tip of OP.…”

Phytohormone biosynthesis and transcriptional analyses provide insight into the main growth stage of male and female cones Pinus koraiensis

“…The time, location, and level of gene expression are all directly regulated by TFs, which are important molecules in this process ( Cai et al., 2021 ). In this study, male and female cones were found to contain 2267 and 1227 genes related to these families of TFs, respectively.…”

Comparative Transcriptomic and Metabolic Analyses Reveal the Coordinated Mechanisms in Pinus koraiensis under Different Light Stress Conditions

“…Transcription factors (TFs) can read the genetic code by binding to cis-regulatory elements to activate or repress gene expression. TFs play a key role in plant development and gene expression regulation, forming complex gene regulatory networks [ 39 , 40 ]. To explore the TFs in response to shading in P. koraiensis , a total of 331 TF genes were identified as DEGs and encoded 68 TF families ( Supplementary Table S7 ).…”