biologia plantarum

Biologia plantarum 66:272-286, 2022 | DOI: 10.32615/bp.2022.029

Cloning and functional analysis of expansin TaEXPA9 orthologs in winter wheat in frigid regions

Z.Y. ZHAO¹, B.Z. HU², X. FENG¹, F.L. LI¹, F.M. HE¹, J.W. WU¹, C.J. XU¹, L. LI¹, Y.Q. XU^{1, *}

¹ College of Life Sciences, Northeast Agricultural University, Harbin 150030, Heilongjiang, P.R. China

² Harbin University, Harbin 150086, Heilongjiang, P.R. China

Long-term low temperatures restrict the regrowth of winter wheat (Triticum aestivum L.), thus decreasing agricultural output. Non-enzymatic expansins, which are related to plant growth, have been reported to respond to drought, salinity, and low-temperature stress. We obtained an expansin 3 gene, TaEXPA9. It is located in winter wheat cv. Dongnong with high cold hardiness. We analyzed the expression patterns of TaEXPA9-A/B/D in this cultivar and conducted a subcellular localization analysis of TaEXPA9-A/B/D in the onion epidermis. Transgenic Arabidopsis thaliana line with EXPA9-A/B/D overexpression was obtained to examine the effects of the orthologous genes of these expansins on plant growth and low-temperature stress resistance. The results showed that EXPA9-A/B/D expression significantly increased at 4 °C, it was higher in the roots than in shoots, and EXPA9-A/B/D was localized in the cell wall. The roots were well-developed in the transgenic A. thaliana, and the growth-related markers and setting rate were better than in the wild-type. Recovery was stronger in the transgenic plants after freezing stress. At low-temperature stress, the antioxidant enzyme activities and content of osmoregulatory substances in the TaEXPA9-A/B/D-overexpressing A. thaliana plants were significantly higher than in the wild-type plants, and the degree of membrane lipid peroxidation was lower. In summary, TaEXPA9 orthologous genes participate in the low-temperature stress response, and they might be of great importance in molecular breeding.

Keywords: Arabidopsis thaliana, expansins, expression analysis, functional validation, TaEXPA9-A/B/D, winter wheat.

Received: December 10, 2021; Revised: April 16, 2022; Accepted: June 9, 2022; Published online: December 6, 2022  Show citation