AUTHOR=Joshi Ila , Kumar Anil , Kohli Deshika , Bhattacharya Ramcharan , Sirohi Anil , Chaudhury Ashok , Jain Pradeep K. 

TITLE=Gall-specific promoter, an alternative to the constitutive CaMV35S promoter, drives host-derived RNA interference targeting Mi-msp2 gene to confer effective nematode resistance

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1007322

DOI=10.3389/fpls.2022.1007322

ISSN=1664-462X

ABSTRACT=<p>One of the major obligate plant parasites causing massive economic crop losses belongs to the class of root-knot nematodes (RKNs). Targeting of major nematode parasitism genes <italic>via</italic> Host Delivered-RNAi (HD-RNAi) to confer silencing is established as one of the most effective approaches to curb nematode infection. Utilizing nematode-responsive root-specific (NRRS) promoters to design a dsRNA molecule targeting approach to hamper nematode parasitism. Here, a previously validated peroxidase gall specific promoter, p<italic>At2g18140</italic>, from <italic>Arabidopsis</italic> was employed to express the dsRNA construct of the nematode effector gene <italic>Mi-msp2</italic> from <italic>Meloidogyne incognita</italic>. <italic>Arabidopsis</italic> RNAi lines of <italic>CaMV35S::Mi-msp2-RNAi</italic> and p<italic>At2g18140::Mi-msp2-RNAi</italic> were compared with control plants to assess the decrease in plant nematode infection. When subjected to infection, the maximum reductions in the numbers of galls, females and egg masses in the <italic>CaMV35S::Mi-msp2-RNAi</italic> lines were 61%, 66% and 95%, respectively, whereas for the p<italic>At2g18140::Mi-msp2-RNAi</italic> lines, they were 63%, 68% and 100%, respectively. The reduction in transcript level ranged from 79%-82% for <italic>CaMV35S::Mi-msp2-RNAi</italic> and 72%-79% for the p<italic>At2g18140::Mi-msp2-RNAi</italic> lines. Additionally, a reduction in female size and a subsequent reduction in next-generation fecundity demonstrate the efficacy and potential of the gall specific promoter p<italic>At2g18140</italic> for utilization in the development of HD-RNAi constructs against RKN, as an excellent alternative to the <italic>CaMV35S</italic> promoter.</p>