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Expression of aquaporin subtypes in cotton under salt stress

Soil salinization is an increasing problem for agricultural systems worldwide, impacting plant growth and crop yield. Although occurring mostly in semiarid regions, soil salinization could affect over >50 % of global arable land by the year 2050 due to climate change and inadequate irrigation practices.  Luckily, salt-tolerant plants have mechanisms to mitigate osmotic and oxidative stresses caused by high salinity through more efficient regulation of ion and water movements, thereby reducing plant water loss and maximizing absorption. One of the main traits underlying salt tolerance is the presence of aquaporins (AQPs), a family of proteins that facilitate the movement of water across cell membranes. Yet in many locations susceptible to soil salinization, the selection of salt tolerant plants in breeding programmes is often carried out in the field by time-consuming and laborious trials. The adoption of molecular markers has the potential to assist selection procedures. 

(A) Control and salt treated cotton plants grown in the study. (B) Infrared gas analyser being used to measure gas exchange rates of leaves. Image credit: Braz et al.

In a recent study published in AoBP, Braz et al. demonstrate that three aquaporins are reliable tools to identify cotton genotypes tolerant to salt stress, based on expression of qPCR-transcripts. Seven cotton cultivars were subjected to high salt stress for 72h and compared to control plants. After the stress treatment, the authors conducted measurements of leaf gas exchange and collected samples for molecular analyses. Consistent down regulation of AQP expression was found in salt tolerant genotypes, i.e. those that were able to maintain photosynthetic rates under salt stress. The authors conclude by recommending the GhPIP1;1 and GhTIP2;1 aquaporins located on the plasma and vacuolar membranes, respectively, as reliable markers for identification of cotton genotypes tolerant to salt stress.

Researcher highlight

Roseane C Santos is an agronomist with an MsC in plant breeding from Rural Federal University of Pernambuco (UFRPE) and a PhD in molecular biology from University of Brasilia (UNB), both in Brazil. Since her early career, she has focused on research involving plant defence through natural resources. Roseane is researcher at the Brazilian Company of Agricultural Research (Embrapa), leading a multidisciplinary team involving researchers and graduate students focusing on plant breeding and biotechnology of oil and fibrous species for tolerance to abiotic stresses. In the last 10 years, Roseane has been dedicated to research in transgenic cotton and the prospects of using useful molecular tags as markers in selection procedures for drought and salinity tolerance.

Roseane is an advisor to graduate students in Agronomy (Federal University of Paraiba, UFPB), Agricultural sciences (Paraiba State University, UEPB) and Genetic improvement of plants (UFRPE). She has authored books and chapters on topics involving genetic improvement, plant ecophysiology, crop management and nutrition. 

Written by William Salter

William (Tam) Salter is a Postdoctoral Research Associate in the School of Life and Environmental Sciences and Sydney Institute of Agriculture at the University of Sydney. He has a bachelor degree in Ecological Science (Hons) from the University of Edinburgh and a PhD in plant ecophysiology from the University of Sydney. Tam is interested in the identification and elucidation of plant traits that could be useful for ecosystem resilience and future food security under global environmental change. He also has an active interest in effective scientific communication.

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