Dehydrins (DHNs) are a sub-group of the late embryogenesis abundant (LEA) proteins.Expression of the DHNs has been associated with the protection of various types of plant cells from osmotic stresses, and are also expressed significantly in seeds towards the end of maturation. Little information is available on DHN genes in jatropha plants, which are known by their ability to survive under numerous severe environmental conditions.
Together with her teachers and colleagues, Dr. S. A. Omar, an Egyptian lady conducting her Ph.D studies in Xishuangbanna Tropical Botanical Garden (XTBG) in 2007-2009, decided to take advantage of the new jatropha expressed sequence tag (EST) analysis to identify cDNAs encoding expressed DHNs and to establish the expression patterns of the DHNs during seed development and natural dehydration. They carried out to validate the importance of DHNs in acquisition of desiccation tolerance of orthodox jatropha seed as a part of a study project to clarify the biochemical and molecular changes during jatropha seed development.
Two full-length cDNAs JcDHN-1 and JcDHN-2 encoding two dehydrins from Jatropha curcas seeds were identified and characterized. Their study found that jatropha seeds synthesized DHNs during maturation and the natural dehydration process. The analysis of conserved domains in JcDHNs revealed that both JcDHN-1 and JcDHN-2 had a dehydrin super-family sequence near the carboxyl end. Moreover, JcDHN-2 showed the presence of superfamily β-N-acetylhexosaminidases of glycoside hydrolase family 20 (GH20).
Their study was probably the first record for GH20 activity in DHNs, which can add to the protection roles and functions of DHNs.
The study entitled “Identification and Differential Expression of Two Dehydrin cDNAs during Maturation of Jatropha curcas Seeds” has been published online in Biochemistry, 78 (5): 485-495, DOI: 10.1134/S0006297913050076