AUTHOR=Khassanova Gulmira , Kurishbayev Akhylbek , Jatayev Satyvaldy , Zhubatkanov Askar , Zhumalin Aybek , Turbekova Arysgul , Amantaev Bekzak , Lopato Sergiy , Schramm Carly , Jenkins Colin , Soole Kathleen , Langridge Peter , Shavrukov Yuri 

TITLE=Intracellular Vesicle Trafficking Genes, RabC-GTP, Are Highly Expressed Under Salinity and Rapid Dehydration but Down-Regulated by Drought in Leaves of Chickpea (Cicer arietinum L.)

JOURNAL=Frontiers in Genetics

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2019.00040

DOI=10.3389/fgene.2019.00040

ISSN=1664-8021

ABSTRACT=<p>Intracellular vesicle trafficking genes, <italic>Rab</italic>, encoding small GTP binding proteins, have been well studied in medical research, but there is little information concerning these proteins in plants. Some sub-families of the <italic>Rab</italic> genes have not yet been characterized in plants, such as <italic>RabC</italic> – otherwise known as <italic>Rab18</italic> in yeast and animals. Our study aimed to identify all <italic>CaRab</italic> gene sequences in chickpea (<italic>Cicer arietinum</italic> L.) using bioinformatics approaches, with a particular focus on the <italic>CaRabC</italic> gene sub-family since it featured in an SNP database. Five isoforms of the <italic>CaRabC</italic> gene were identified and studied: <italic>CaRabC-1a, -1b, -1c, -2a</italic> and <italic>-2a<sup>∗</sup></italic>. Six accessions of both Desi and Kabuli ecotypes, selected from field trials, were tested for tolerance to abiotic stresses, including salinity, drought and rapid dehydration and compared to plant growth under control conditions. Expression analysis of total and individual <italic>CaRabC</italic> isoforms in leaves of control plants revealed a very high level of expression, with the greatest contribution made by <italic>CaRabC-1c</italic>. Salinity stress (150 mM NaCl, 12 days in soil) caused a 2-3-fold increased expression of total <italic>CaRabC</italic> compared to controls, with the highest expression in isoforms <italic>CaRabC-1c, -2a<sup>∗</sup></italic> and <italic>-1a</italic>. Significantly decreased expression of all five isoforms of <italic>CaRabC</italic> was observed under drought (12 days withheld water) compared to controls. In contrast, both total <italic>CaRabC</italic> and the <italic>CaRabC-1a</italic> isoform showed very high expression (up-to eight-fold) in detached leaves over 6 h of dehydration. The results suggest that the <italic>CaRabC</italic> gene is involved in plant growth and response to abiotic stresses. It was highly expressed in leaves of non-stressed plants and was down-regulated after drought, but salinity and rapid dehydration caused up-regulation to high and very high levels, respectively. The isoforms of <italic>CaRabC</italic> were differentially expressed, with the highest levels recorded for <italic>CaRabC-1c</italic> in controls and under salinity stress, and for <italic>CaRabC-1a</italic> – in rapidly dehydrated leaves. Genotypic variation in <italic>CaRabC-1a</italic>, comprising eleven SNPs, was found through sequencing of the local chickpea cultivar Yubileiny and germplasm ICC7255 in comparison to the two fully sequenced reference accessions, ICC4958 and Frontier. Amplifluor-like markers based on one of the identified SNPs in <italic>CaRabC-1a</italic> were designed and successfully used for genotyping chickpea germplasm.</p>