Genome Identification and Evolutionary Analysis of LBD Genes and Response to Environmental Factors in Phoebe bournei

Abstract

Phoebe bournei is nationally conserved in China due to its high economic value and positive effect on the ecological environment. P. bournei has an excellent wood structure, making it useful for industrial and domestic applications. Despite its importance, there are only a few studies on the lateral organ boundary domain (LBD) genes in P. bournei. The LBD gene family contributes to prompting rooting in multiple plant species and therefore supports their survival directly. To understand the LBD family in P. bournei, we verified its characteristics in this article. By comparing the sequences of Arabidopsis and identifying conserved domains and motifs, we found that there were 38 members of the LBD family in P. bournei, which were named PbLBD1 to PbLBD38. Through evolutionary analysis, we found that they were divided into two different populations and five subfamilies in total. The LBD gene family in P. bournei (Hemsl.) Yang species had two subfamilies, including 32 genes in Class I and 6 genes in Class II. It mainly consists of a Lateral Organ Boundary (LOB) conservative domain, and the protein structure is mostly “Y”-shaped. The gene expression pattern of the LBD gene family showed that the LBD genes were mainly expressed in lateral organs of plants, such as flowers and fruits. The response of LBD transcription factors to red and blue light was summarized, and several models of optogenetic expression regulation were proposed. The effect of regulatory mechanisms on plant rooting was also predicted. Moreover, quantitative real-time PCR (qRT-PCR) revealed that most PbLBDs were differentially expressed under cold, heat, drought, and salt stresses, indicating that PbLBDs might play different functions depending on the type of abiotic stress. This study provides the foundation for further research on the function of LBD in this tree species in the future.

Abiotic Stress Tolerance Boosted by Genetic Diversity in Plants

“…In light of this, rigorous validation of candidate associations is a non-negotiable requirement [55] before one can proceed with more downstream applications. It is as part of this corroboration endeavor that Zhao et al [34], Ma et al [35], and Guo et al [36] envisioned their works, using alfalfa (Medicago sativa), Phoebe bournei (a widely conserved tree in China because of its economic and ecological value), and sorghum (Sorghum bicolor) as study organisms for multiple abiotic stresses, such as salt (all three species), drought (the former two taxa), and heat (the second species). Performing integrated assessment of multiple stresses such as these also enables long-standing questions concerning the scale of molecular pleiotropism beneath concomitant abiotic stresses to be addressed [56], a matter which has already been approached in this Special Issue by Wirojsirasak et al [33] in a multi-environment framework [12], but has yet to be addressed in a multi-trait setup [57].…”

“…This work opens the door to more focused indirect marker-based breeding techniques [58,59], which will increase the yield and quality of this key crop. Similarly, Ma et al [35] considered 38 putative LBD (lateral organ boundary domain) gene sequences (5 of which were targeted with qRT-PCR) in P. bournei, a target for conservation, in a multi-stress frame. Meanwhile, in another work, the molecular pleiotropism was reinforced across multiple abiotic stresses [60].…”

“…Data Availability Statement: For data availability, please see the original articles [31][32][33][34][35][36][37] within the Special Issue "Abiotic Stress Tolerance and Genetic Diversity in Plants" (https://www.mdpi.com/ journal/ijms/special_issues/80P9M9NK87 accessed on 24 March 2023).…”