Morphological, physiological, biochemical, and transcriptome studies reveal the importance of transporters and stress signaling pathways during salinity stress in Prunus

Authors: ACHARYA, BISWA - University Of California; Sandhu, Devinder; DUEÑAS, CHRISTIAN - University Of California; DUEÑAS, MARCO - University Of California; Pudussery, Manju; KAUNDAL, AMITA - Utah State University; Ferreira, Jorge; Suarez, Donald; Skaggs, Todd

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2021
Publication Date: 1/24/2022
Citation: Acharya, B.R., Sandhu, D., Dueñas, C., Dueñas, M., Pudussery, M.V., Kaundal, A., Ferreira, J.F., Suarez, D.L., Skaggs, T.H. 2022. Morphological, physiological, biochemical, and transcriptome studies reveal the importance of transporters and stress signaling pathways during salinity stress in Prunus. Scientific Reports. 12. Article 1274. https://doi.org/10.1038/s41598-022-05202-1.
DOI: https://doi.org/10.1038/s41598-022-05202-1

Interpretive Summary: Almond is an economically important crop in the United States, with over 80% of the world's almond production coming from California and contributing over 21.5 billion dollars to California's economy in 2014. Almond trees are sensitive to salinity and crop yields are lower when grown on saline soils. Identifying salt-tolerant rootstocks is vital to developing and maintaining economic irrigated agriculture under saline conditions. In this investigation, we performed phenotypic, physiological, and biochemical analyses to compare the salinity tolerance of two commercial rootstocks, 'Rootpac 40' and 'Nemaguard'. Under saline conditions, the rootstocks displayed contrasting responses, with 'Rootpac 40' showing a significantly better survival rate, less sodium, chloride, and proline accumulation, and more potassium accumulation in leaves than 'Nemaguard'. RNA sequencing (RNA-Seq) analysis of 'Rootpac 40' and 'Nemaguard' identified several candidate genes that may be critical during salinity stress in almond rootstocks. Suitable candidate genes can be further explored for their salinity tolerance roles and used to breed new salt-tolerant rootstocks. Hence, our results will help almond breeders and geneticists develop new salt-tolerant varieties, allowing farmers to increase crop yields in marginal lands.

Technical Abstract: The almond crop has high economic importance on a global scale, but its sensitivity to salinity stress can cause severe yield losses. Salt-tolerant rootstocks are vital for crop economic feasibility under saline conditions. Two commercial rootstocks submitted to salinity, and evaluated through different parameters, had contrasting results with the survival rates of 90.6% for ‘Rootpac 40’ (tolerant) and 38.9% for ‘Nemaguard’ (sensitive) under salinity (Electrical conductivity of water'='3 dS m-1). Under salinity, ‘Rootpac 40’ accumulated less Na and Cl and more K in leaves than ‘Nemaguard’. Increased proline accumulation in ‘Nemaguard’ indicated that it was highly stressed by salinity compared to ‘Rootpac 40’. RNA-Seq analysis revealed that a higher degree of differential gene expression was controlled by genotype rather than by treatment. Differentially expressed genes (DEGs) provided insight into the regulation of salinity tolerance in Prunus. DEGs associated with stress signaling pathways and transporters may play essential roles in the salinity tolerance of Prunus. Some additional vital players involved in salinity stress in Prunus include CBL10, AKT1, KUP8, Prupe.3G053200 (chloride channel), and Prupe.7G202700 (mechanosensitive ion channel). Genetic components of salinity stress identified in this study may be explored to develop new rootstocks suitable for salinity-affected regions.