The role of PagMYB73A in salinity tolerance in poplars

Poplar trees, characterized by their rapid growth and broad adaptability, are a fast-growing timber species. However, in the northern regions of China, their growth has been consistently impeded by salt stress. MYB family transcription factors (TFs) play a critical role in stress response and development. Nevertheless, the function of specific MYB genes remains unclear, especially regarding their role in salt tolerance. Previous studies have identified that PagMYB73 (a homolog gene of PagMYB73A in poplar) can be induced by salt stress, with its homologous gene MYB73 in Arabidopsis participating in lateral root growth and stress resistance by regulating auxin biosynthesis. However, the mechanism by which PagMYB73A contributes to salt tolerance in poplar remains unclear.

Forestry Research published online a paper entitled “PagMYB73A enhances poplar salt tolerance by facilitating adventitious roots elongation and stomata density” on 24 January 2024.

Initially, this study identified ten homologous proteins of PagMYB73A through a blastp search on the NCBI website, among which the XP_002301201.1 protein from Populus trichocarpa demonstrated significant homology. These homologous proteins are characterized by the conserved R2R3-MYB domain. Interestingly, subcellular localization of PagMYB73A revealed that, unlike typical transcription factors, PagMYB73A is not only localized in the nucleus but also distributed throughout the cell. Further experiments demonstrated that overexpressing PagMYB73A in poplars under salt stress conditions led to a significant increase in adventitious root length and root dry weight, with a concomitant decrease in plant height. This was supported by the finding that PagMYB73A overexpression resulted in enhanced expression of genes associated with adventitious root development under salt stress.

Additionally, PagMYB73A overexpression improved overall root growth metrics but reduced fine root development under these conditions, indicating a nuanced influence on root architecture.Moreover, PagMYB73A was shown to maintain stomatal density under salt stress, which is crucial for plant stress adaptation, and to reduce cellular membrane damage, as indicated by lower MDA content in overexpressing lines compared to wild type.  Under both normal and salt stress conditions, no significant differences were observed in the activities of SOD, POD, and CAT between OE (overexpressing) and WT (wild-type) plants. These findings further corroborate that PagMYB73A enhances salt tolerance in poplar through the regulation of the MDA pathway.

In concluosion, these findings underscore PagMYB73A's multifaceted role in enhancing poplar salt tolerance through various mechanisms, including promoting adventitious root growth, regulating root architecture, maintaining stomatal density, and protecting cellular membranes from oxidative damage. This research not only highlights the intricate response strategies plants employ to cope with abiotic stress but also provides valuable insights for breeding more resilient poplar varieties.

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References

DOI

10.48130/forres-0023-0032

Original Source URL

https://www.maxapress.com/article/doi/10.48130/forres-0023-0032

Authors

Xia Jin1, Kai Zhao¹, Jia Hu¹, Oliver Gailing², , Lieding Zhou¹, Shuhui Du¹, Youzhi Han^1,* ,  & Shengji Wang^{1, *}

Affiliations

^1.College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, China

^2.Forest Genetics and Forest Tree Breeding, Georg-August University of Göttingen, Göttingen 37077, Germany

About Shengji Wang

Shengji Wang currently works at the State Key Laboratory of Tree Breeding, Northeast Forestry University. He does research in Agricultural Plant Science.