Recently, professor Liu Shuwei from the School of Life Sciences of Shandong University published a research article entitled "Ca²⁺-dependent TaCCD1 cooperates with TaSAUR215 to enhance plasma membrane H⁺-ATPase activity and alkali stress tolerance by inhibiting PP2C-mediated dephosphorylation of TaHA2 in wheat" in Molecular Plant (IF, 21.949). This study revealed the molecular mechanism of Ca²⁺ binding protein TaCCD1 in regulating wheat alkali tolerance, which provided a theoretical basis and gene resources for wheat alkali resistance breeding.

Soil salinization is an important factor affecting crop yield. In addition to the neutral salt NaCl and Na₂SO₄, the salinized soil also contains alkaline salt NaHCO₃ and Na₂CO₃. Compared with neutral salt stress, the alkaline stress will cause a higher pH and have a much more severe effect on plants. However, little attention has been paid to the mechanisms underlying plant responses to alkali stress。 Shanrong 4 (SR4) is an alkalinity-tolerant wheat introgression line selected from the derivatives of asymmetric somatic hybrids between the bread wheat cultivar Jinan177 (JN177) and tall wheatgrass (Thinopyrum ponticum), which is a good material to exploit the molecular mechanism of wheat alkali-tolerance.

It was found that the alkali-resistance of SR4 was related to its high PM H⁺-ATPase activity and proton efflux ability, and calcium plays a vital role in the SR4 response to alkali stress. The authors identified a calcium ion binding proteinTaCCD1, which is specifically up-regulated in SR4 roots under alkali stress. Overexpression of TaCCD1 in wheat promotes PM H⁺-ATPase activity and enhances wheat tolerance to alkali stress, while down-regulation of its expression reduces PM H⁺-ATPase activity and results in wheat sensitivity to alkali stress, indicating that TaCCD1 responds to alkali stress via enhancing proton efflux and PM H⁺-ATPase activity. Further study found that TaCCD1 interacted with one early auxin-responsive protein TaSAUR215 and enhanced the inhibition of TaSAUR215 on the activity of twoD-cladetype 2C protein phosphatases, TaPP2C.D1 and TaPP2C.D8 (TaPP2C.D1/8), while TaPP2C.D1/8 negatively modulated alkali stress tolerance by inhibiting PM H⁺-ATPase activity via dephosphorylatingthe penultimate threonine residue (Thr926) at the C-terminalof TaHA2.

This research was supported by grants from the National Natural Science Foundation of China, the Natural Science Foundation of Shandong Province, the Agricultural Variety Improvement Project of Shandong Province and National Key R&D Program of China. Cui Minghan, a PhD candidate at the School of Life Sciences, is the first author of this paper, and professor Liu Shuwei is the corresponding author. Professor Xia Guangmin provided guidance and assistance to the work.

Professor Liu Shuwei's team has long been engaged in the identification of functional genes and the research of molecular mechanism of salt-alkali tolerance, high quality, high yield and other related traits of wheat. In recent years, they have published a few research articles in academic journals including Molecular Plant, Plant Cell, Plant Biotechnology Journal, Plant Journal, Journal of Experimental Botany and Genetics.

Link to the article:

https://www.cell.com/molecular-plant/fulltext/S1674-2052(23)00010-2