Genome-wide identification of the AlkB homologs gene family, PagALKBH9B and PagALKBH10B regulated salt stress response in Populus

Abstract

The AlkB homologs (ALKBH) gene family regulates N6-methyladenosine (m6A) RNA methylation and is involved in plant growth and the abiotic stress response. Poplar is an important model plant for studying perennial woody plants. Poplars typically have a long juvenile period of 7–10 years, requiring long periods of time for studies of flowering or mature wood properties. Consequently, functional studies of the ALKBH genes in Populus species have been limited. Based on AtALKBHs sequence similarity with Arabidopsis thaliana, 23 PagALKBHs were identified in the genome of the poplar 84K hybrid genotype (P. alba × P. tremula var. glandulosa), and gene structures and conserved domains were confirmed between homologs. The PagALKBH proteins were classified into six groups based on conserved sequence compared with human, Arabidopsis, maize, rice, wheat, tomato, barley, and grape. All homologs of PagALKBHs were tissue-specific; most were highly expressed in leaves. ALKBH9B and ALKBH10B are m6A demethylases and overexpression of their homologs PagALKBH9B and PagALKBH10B reduced m6A RNA methylation in transgenic lines. The number of adventitious roots and the biomass accumulation of transgenic lines decreased compared with WT. Therefore, PagALKBH9B and PagALKBH10B mediate m6A RNA demethylation and play a regulatory role in poplar growth and development. Overexpression of PagALKBH9B and PagALKBH10B can reduce the accumulation of H2O2 and oxidative damage by increasing the activities of SOD, POD, and CAT, and enhancing protection for Chl a/b, thereby increasing the salt tolerance of transgenic lines. However, overexpression lines were more sensitive to drought stress due to reduced proline content. This research revealed comprehensive information about the PagALKBH gene family and their roles in growth and development and responsing to salt stress of poplar.

Identification of m6A RNA methylation genes in Oryza sativa and expression profiling in response to different developmental and environmental stimuli

“…It highlights the intricate regulatory mechanisms underlying plant growth and adaptation. A previous study reveals that ALKBH10B specifically regulates the floral transition process by demethylating transcripts of key flowering time genes, including flowering locus T (FT) and squamosa promoter binding protein-like 3 (SPL3) in Arabidopsis [ 86 ]. Another study focuses that YTH proteins are involved in various plant processes, including embryogenesis, flowering transition, root development, stem cell fate determination, circadian rhythm, leaf morphology, leaf coat development, nitrate signalling, fruit maturation, gametophyte development, phytohormone responses, and stress responses [ 87 ].…”

The AlkB Homolog SlALKBH10B Negatively Affects Drought and Salt Tolerance in Solanum lycopersicum

“…Conversely, in cotton, GhALKBH10B was found to be downregulated under different abiotic stresses [ 15 ]. Similarly, in Populus , salt treatment induced the expression of PagALKBH10B [ 33 ]. In this study, we observed significant upregulation of SlALKBH10B expression in response to ABA, drought, and salt treatments ( Figure 2 C,G,H).…”

“…In cotton, silencing GhALKBH10B led to improved salinity tolerance [ 15 ], and mutation of GhALKBH10B enhanced drought resistance during the seedling stage [ 16 ], indicating a negative regulation of both salt and drought tolerance by GhALKBH10B. Moreover, heterologous expression of PagALKBH10B in Arabidopsis resulted in increased salt tolerance but decreased drought tolerance in transgenic lines [ 33 ], implying a positive regulation of salt tolerance and a negative regulation of drought tolerance by PagALKBH10B. These findings highlight the diverse and even opposing biological functions of ALKBH10B in regulating salt and drought tolerance across different plant species.…”

N6‐methyladenosine mRNA methylation positively regulated the response of poplar to salt stress

“…m 6 A/A ratio measurement is referenced and refined following our previous research (Zhao, Guo et al, 2022). Total RNA was isolated from the leaves by TRIzol reagent (ET121, TransGenBiotech), and RNA quality was detected by spectrophotometer (Thermo Scientific) and agarose gel electrophoresis.…”