Dual mechanisms of salinity tolerance in wheat germplasm lines W4909 and W4910

Authors: Wang, Richard; Xu, Steven; Monaco, Thomas; Robbins, Matthew

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2024
Publication Date: 11/30/2024
Citation: Wang, R., Xu, S.S., Monaco, T.A., Robbins, M.D. 2024. Dual mechanisms of salinity tolerance in wheat germplasm lines W4909 and W4910. International Journal of Molecular Sciences. https://doi.org/10.3390/ijms252312892.
DOI: https://doi.org/10.3390/ijms252312892

Interpretive Summary: Soil salinity adversely affects plant growth and development, reducing yield of most crops including wheat. Previously released salt-tolerant wheat germplasm lines W4909 and W4910 had been utilized by few wheat breeders due to the lack of molecular markers associated with salt tolerance in these lines. We developed four molecular markers that can trace back to one of the two parentts of W4909 and W4910. We got rid of one of the molecular markers that was undesirable for causing chromosome instability if lines having the marker were used in wheat crosses. We identified lines uniform for either carrying or lacking the other three markers so that they can be used in future research. In this study, we demonstrated that the two mechanisms of salt tolerance, sodium exclusion and sodium sequestration (tissue tolerance), are present in W4909 and W4910 and separately traceable to the two parental lines.

Technical Abstract: Soil salinity adversely affects plant growth and development, reducing yield of most crops including wheat. The highly salt-tolerant wheat germplasm lines W4909 and W4910 were derived from a cross between two moderately salt-tolerant lines, the Chinese Spring (CS)/Thinopyrum junceum disomic addition line AJDAj5 (AJ) and the Ph-inhibitor line (Ph-I) derived from CS/Aegilops speltoides. Molecular markers for gene introgressions in W4909 and W4910 were not reported. Four sequence tagged sites (STS) molecular markers of Ph-I were developed and tested in the above-mentioned lines and F2 progenies of the two crosses, Anza (AZ) × 4740 (sib of W4910) and Yecora Rojo (YR) × 4728 (sib of W4909). Additionally, homogeneity was assessed in several derivatives of W4909, 4728, W4910, and 4740 using the four markers. The four STS markers are not associated with salt tolerance, but an indication of the transfer of chromatin in 3B chromosome of Ae. speltoides via Ph-I. Moreover, salt tolerance and leaf sodium concentration were determined in CS, AJ, Ph-I, 7151 (progeny of W4909), 7157 (progeny of W4910), AZ, and YR under salt treatment and control. Surprisingly, AJ had the lowest leaf sodium concentration under the control and salt treatment, indicating greater sodium exclusion than that in CS, AZ, and YR. This low level of leaf sodium concentration was heritable from 4740 to its hybrid progenies. On the other hand, the higher leaf sodium concentration indicative of the tissue tolerance to salinity in Ph-I had been inherited by both W4909 and W4910 and then transmitted to their hybrid progenies. One offspring line in each of W4909 and W4910 (7762 and 7159, respectively) were homozygous for the three molecular markers and lacked the marker psr1205 of Su1-Ph1 gene, making them better materials than the original lines for future research such as whole-genome sequencing and gene mining. The implications of these findings toward the utilization of W4909 and W4910 in breeding salt tolerant wheat cultivars are discussed.