Chitinase genes from Metarhizium anisopliae for the control of whitefly in cotton

Abstract

Entomopathogenic fungi produces endochitianses, involved in the degradation of insect chitin to facilitate the infection process. Endochitinases ( Chit1 ) gene of family 18 glycosyl hydrolyses were amplified, cloned and characterized from genomic DNA of two isolates of Metarhizium anisopliae. Catalytic motif of family 18 glycosyl hydrolyses was found in Chit1 of M. anisopliae , while no signal peptide was found in any isolate, whereas substrate-binding motif was found in Chit1 of both isolates. Phylogenetic analysis revealed the evolutionary relationship among the fungal chitinases of Metarhizium . The Chit1 amplified were closely related to the family 18 glycosyl hydrolyses. Transient expressions of Chit1 in cotton plants using Geminivirus-mediated gene silencing vector of Cotton Leaf Crumple Virus (CLCrV) revealed the chitinase activity of Chit1 genes amplified from both of the isolates of M. anisopliae when compared with the control. Transformed cotton plants were virulent against fourth instar nymphal and adult stages of Bemisia tabaci which resulted in the mortality of both fourth instar nymphal and adult B. tabaci. Thus, the fungal chitinases expressed in cotton plants played a vital role in plant defence against B. tabaci . However, further studies are required to explore the comparative effectiveness of chitinases from different fungal strains against economically important insect pests.

Seafood Waste as Attractive Source of Chitin and Chitosan Production and Their Applications

“…The γ-chitin displays a mixture of both positions [27,28]. Chitin is widely distributed in nature and is the main element of the marine invertebrate exoskeleton and can be found in the structure of insects, arthropods, and molluscs [24][25][26]. Figure 2 presents the main sources of chitin production and its extraction.…”

Tiny Flies: A Mighty Pest That Threatens Agricultural Productivity—A Case for Next-Generation Control Strategies of Whiteflies

“…Another class of insecticidal proteins that has been explored against whiteflies is “chitinases”. Although entomopathogenic fungi, e.g., Metarhizium sps., Isaria fumosorosea , etc., producing chitinase is an effective biological control agent for whiteflies [ 163 ], very few chitinases are found to be toxic against whiteflies [ 164 , 165 ]. An organized and efficient exploration of fern biodiversity has been performed in want of anti-whitefly protein(s) and a protein viz., Tma12 (LC 50 = 1.49 μg/mL in insect bioassay using artificial diet) has been discovered [ 111 ].…”

Biotechnological interventions for the sustainable management of a global pest, whitefly (Bemisia tabaci)

“…The expression of insecticidal proteins in transgenic plants may be associated with unwanted side effects in beneficial and other nontarget organisms; however, mannose‐binding lectins, such as onion leaf lectin, are nontoxic to humans and animals and thus safe for the effective control of sap‐sucking pests (Chougule & Bonning, 2012). In cotton plants, expression of the chitinase ( Chit 1 ) gene of Metarhizium anisopliae , an entomopathogenic fungus that degrades insect chitin to facilitate infection, has been found to lead to the mortality of both fourth‐instar nymphs and adult whiteflies (Anwar et al ., 2019). In addition, chitinases have the potential to suppress phyto‐pathogenic activity.…”