Identification and evolutionary relationships of partial gene sequences from dehydrin group in three species of cacti

Abstract

Dehydrins or Group 2 Late Embryogenesis Abundant(LEA) proteins play an important role in the response and adaptationto different types of abiotic stresses such as droughts, high salinityand low temperatures. Using PCR techniques, we identified threegene fragments that encoded dehydrin-like proteins in three cactispecies Opuntia ficus-indica (OpfiDHN-like), Leuchtenbergia principis(LepDHN-like) and Mammillaria bombycina (MabDHN-like).Bioinformatic sequence analysis showed an identity between 96 and97% with the Opuntia streptacantha dehydrin 1 (OpsDHN1) gene,demonstrating that the amplified fragments corresponded to dehydrin-like gene sequences, and that the designed oligonucleotideswere effective for similar gene amplification in different cacti genera.Multiple OpfiDHN-like, LepDHN-like and MabDHN-like alignmentsshowed that they possessed three repetitions of the conservedK segment. Also, a histidine rich motif was found, which is believedto facilitate the binding of these proteins with metal ions that probablyevolved differently in the Opuntioidea and Cactoidea subfamiliesof the Cactaceae family. Bioinformatic tools demonstratedthat each of the three partial amino acid sequences corresponded toacidic, highly hydrophilic, and disordered protein fragments, whichare characteristics of dehydrin proteins. Phylogenetic analysis usingmaximum parsimony, indicated that cacti dehydrins-like proteinswere monophyletic, as well as those of other families.