Chitinase of Trichoderma longibrachiatum for control of Aphis gossypii in cotton plants

Chitinase-producing fungi have now engrossed attention as one of the potential agents for the control of insect pests. Entomopathogenic fungi are used in different regions of the world to control economically important insects. However, the role of fungal chitinases are not well studied in their infection mechanism to insects. In this study, Chitinase of entomopathogenic fungi Trichoderma longibrachiatum was evaluated to control Aphis gossypii. For this purpose, fungal chitinase (Chit1) gene from the genomic DNA of T. longibrachiatum were isolated, amplified and characterised. Genomic analysis of the amplified Chit1 showed that this gene has homology to family 18 of glycosyl hydrolyses. Further, Chit1 was expressed in the cotton plant for transient expression through the Geminivirus-mediated gene silencing vector derived from Cotton Leaf Crumple Virus (CLCrV). Transformed cotton plants showed greater chitinase activity than control, and they were resistant against nymphs and adults of A. gossypii. About 38.75% and 21.67% mortality of both nymphs and adults, respectively, were observed by using Chit1 of T. longibrachiatum. It is concluded that T. longibrachiatum showed promising results in controlling aphids by producing fungal chitinase in cotton plants and could be used as an effective method in the future.

Genome-wide and molecular characterization of the DNA replication helicase 2 (DNA2) gene family in rice under drought and salt stress

Rice plants experience various biotic (such as insect and pest attack) and abiotic (such as drought, salt, heat, and cold etc.) stresses during the growing season, resulting in DNA damage and the subsequent losses in rice production. DNA Replication Helicase/Nuclease2 (DNA2) is known to be involved in DNA replication and repair. In animals and yeast DNA2 are well characterized because it has the abilities of both helicase and nuclease, it plays a crucial role in DNA replication in the nucleus and mitochondrial genomes. However; they are not fully examined in plants due to less focused on plants damage repair. To fill this research gap, the current study focused on the genome-wide identification and characterization of OsDNA2 genes, along with analyses of their transcriptional expression, duplication, and phylogeny in rice. Overall, 17 OsDNA2 members were reported to be found on eight different chromosomes (2, 3, 4, 6, 7, 9, 10, and 11). Among these chromosomes (Chr), Chr4 contained a maximum of six OsDNA2 genes. Based on phylogenetic analysis, the OsDNA2 gene members were clustered into three different groups. Furthermore, the conserved domains, gene structures, and cis-regulatory elements were systematically investigated. Gene duplication analysis revealed that OsDNA2_2 had an evolutionary relationship with OsDNA2_14, OsDNA2_5 with OsDNA2_6, and OsDNA2_1 with OsDNA2_8. Moreover, results showed that the conserved domain (AAA_11 superfamily) were present in the OsDNA2 genes, which belongs to the DEAD-like helicase superfamily. In addition, to understand the post-transcriptional modification of OsDNA2 genes, miRNAs were predicted, where 653 miRNAs were reported to target 17 OsDNA2 genes. The results indicated that at the maximum, OsDNA2_1 and OsDNA2_4 were targeted by 74 miRNAs each, and OsDNA2_9 was less targeted (20 miRNAs). The three-dimensional (3D) structures of 17 OsDNA2 proteins were also predicted. Expression of OsDNA2 members was also carried out under drought and salt stresses, and conclusively their induction indicated the possible involvement of OsDNA2 in DNA repair under stress when compared with the control. Further studies are recommended to confirm where this study will offer valuable basic data on the functioning of DNA2 genes in rice and other crop plants.