Genome-wide identification of XTH gene family in Musa acuminata and response analyses of MaXTHs and xyloglucan to low temperature

Genomics reveal population structure, genetic diversity and evolutionary history of Phyllostachys edulis (moso bamboo) in global natural distribution

Introduction

Moso bamboo (Phyllostachys edulis) is widespread in natural forests over large areas in China.

Methods

Here we collected 193 individuals of moso bamboo from 37 natural populations in China's distribution area. Genotyping by sequencing (GBS) was employed to elucidate the genetic diversity, genetic structure, selection pressure, history and adaptive distribution prediction of moso bamboo.

Results

The results revealed that the moso bamboo in China can be divided into central α, eastern β and southern γ subpopulations, with the α-subpopulation presumed to be the origin center. Notably, the genetic diversity of moso bamboo populations were relatively low, and the heterozygotes were excess. At the subpopulation level, the genetic diversity of α-subpopulation was the highest and that of β-subpopulation was the lowest. Analysis of population selection pressure during the transmission of moso bamboo indicated significant genetic differences among subpopulations. Furthermore, 3681 genes related to adaptability, stress resistance, photosynthesis, and hormone were identified from the selected regions. Four SNP markers developed and validated. Based on the population dynamics history and distribution simulation, we found that the distribution of moso bamboo has been influenced by the climate change in geological history.

Discussion

These findings hold significant implications for enhancing our genetic comprehension of bamboo populations and exploring germplasm resources.

Genome-Wide Identification of Xyloglucan Endotransglucosylase/Hydrolase Multigene Family in Chinese Jujube (Ziziphus jujuba) and Their Expression Patterns Under Different Environmental Stresses

The Xyloglucan endotransglucosylase/hydrolase (XTH) family, a group of cell wall-modifying enzymes, plays crucial roles in plant growth, development, and stress adaptation. The quality and yield of Chinese jujube (Ziziphus jujuba) fruit are significantly impacted by environmental stresses, including excessive salinity, drought, freezing, and disease. However, there has been no report of the XTH encoding genes present in the Chinese jujube genome and their response transcription level under various stresses. This study provides an in-depth analysis of ZjXTH genes in the genome of Chinese jujube and elucidates their structural motifs, regulatory networks, and expression patterns under various stresses. A total of 29 ZjXTH genes were identified from the Ziziphus jujuba genome. Phylogenetic analysis classifies ZjXTH genes into four distinct groups, while conserved motifs and domain analyses reveal coordinated xyloglucan modifications, highlighting key shared motifs and domains. Interaction network predictions suggest that ZjXTHs may interact with proteins such as Expansin-B1 (EXPB1) and Pectin Methylesterase 22 (PME22). Additionally, cis-regulatory element analysis enhances our understanding of Chinese jujube plant's defensive systems, where TCA- and TGACG-motifs process environmental cues and orchestrate stress responses. Expression profiling revealed that ZjXTH1 and ZjXTH5 were significantly upregulated under salt, drought, freezing, and phytoplasma infection, indicating their involvement in biotic and abiotic stress responses. Collectively, these findings deepen our understanding of the functional roles of Chinese jujube XTHs, emphasizing their regulatory function in adaptive responses in Chinese jujube plants.

Changes in hemicellulose metabolism in banana peel during fruit development and ripening

Hemicellulose is key in determining the fate of plant cell wall in almost all growth and developmental stages. Nevertheless, there is limited knowledge regarding its involvement in the development and ripening of banana fruit. This study investigated changes in the temporal-spatial distribution of various hemicellulose components, hemicellulose content, activities of the main hydrolysis enzymes, and transcription level of the main hemicellulose-related gene families in banana peels. Both hemicellulose and xylan contents were positively correlated to the fruit firmness observed in our previous study. On the contrary, the xylanase activity was negatively correlated to xylan content and the fruit firmness. The vascular bundle cells, phloem, and cortex of bananas are abundant in xyloglucan, xylan, and mannan contents. Interestingly, the changes in the signal intensity of the CCRC-M104 antibody recognizing non-XXXG type xyloglucan are positively correlated to hemicellulose content. According to RNA-Seq analysis, xyloglucan and xylan-related genes were highly active in the early stages of growth, and the expression of MaMANs and MaXYNs increased as the fruit ripened. The abundance of plant hormonal and growth-responsive cis-acting elements was detected in the 2 kb upstream region of hemicellulose-related gene families. Interaction between hemicellulose and cell wall-specific proteins and MaKCBP1/2, MaCKG1, and MaHKL1 was found. The findings shed light on cell wall hemicellulose's role in banana fruit development and ripening, which could improve nutrition, flavor, and reduce postharvest fruit losses.