Plant Genomics

Biography

Biography: M Jayanthi

Abstract

There are several reports of successful application of RNAi for functional validation of various genes of plant parasitic nematodes particularly under in vitro conditions. Delivering dsRNA to plant parasitic nematodes has been technically challenging, because these obligatory parasites requires living host for feeding and the pre-parasitic nematodes are of non feeding and do not ingest fluid at this stage. Several housekeeping and parasitism genes were silenced in vitro for functional studies using this approach are well documented. Due to grand success in functional genomics, RNAi has emerged as versatile tool with wide range of applications in plant biology. Recent developments in RNAi led to the identification of core RNAi components in many eukaryotes and have envisioned researchers to adopt this tool for wider applications in crop improvement including engineering crop plants against plant parasitic nematode menace. In the past decade, various studies indicated key developments in the RNAi machinery and also whole genome sequence data available for few of the plant-parasitic nematodes provides a new horizon for the successful exploitation of RNAi for nematode control. Expression of dsRNA, corresponding to the nematode target gene through host plant, mediates the production of siRNAs. Based on the sequence similarity between the siRNAs and the corresponding target mRNA, silencing is achieved upon nematode feeding. Although most of the reports successfully utilized RNAi for studying the gene function in vitro, however, they were not technically feasible to use as nematode control under field conditions. And major hurdle for potential application of plant-mediated RNAi was whether nematodes ingest dsRNA when feeding on plant cells expressing dsRNA constructs. The delivery of parasites gene-specific dsRNA through the host may be more effective and appropriate method for nematode control. Host-delivered RNAi appears to be most promising strategy for nematode control. Based on the choice of the target gene selected, it can be broadly categorized as dsRNA against the targets which are constitutively expressed throughout nematode life cycle, genes involved in nematode development, neurotransmission, nematode effectors/parasitism genes. Some of these nematode target genes have been validated experimentally through in vitro RNAi experiments in C. elegans and other plant parasitic nematodes. In our own laboratory it is found that silencing of several genes like FLP 18 and MSP1 can reduce the nematode attack in brinjal. All the above reports both under in vitro and in planta strongly indicate that utilization of several key nematode genes can be used for silencing through in planta RNAi for developing successful management of root knot and other important plant parasitic nematodes.