AUTHOR=Shivakumara Tagginahalli N. , Chaudhary Sonam , Kamaraju Divya , Dutta Tushar K. , Papolu Pradeep K. , Banakar Prakash , Sreevathsa Rohini , Singh Bhupinder , Manjaiah K. M. , Rao Uma 

TITLE=Host-Induced Silencing of Two Pharyngeal Gland Genes Conferred Transcriptional Alteration of Cell Wall-Modifying Enzymes of Meloidogyne incognita vis-à-vis Perturbed Nematode Infectivity in Eggplant

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00473

DOI=10.3389/fpls.2017.00473

ISSN=1664-462X

ABSTRACT=<p>The complex parasitic strategy of <italic>Meloidogyne incognita</italic> appears to involve simultaneous expression of its pharyngeal gland-specific effector genes in order to colonize the host plants. Research reports related to effector crosstalk in phytonematodes for successful parasitism of the host tissue is yet underexplored. In view of this, we have used <italic>in planta</italic> effector screening approach to understand the possible interaction of pioneer genes (<italic>msp-18</italic> and <italic>msp-20</italic>, putatively involved in late and early stage of <italic>M. incognita</italic> parasitism, respectively) with other unrelated effectors such as cell-wall modifying enzymes (CWMEs) in <italic>M. incognita</italic>. Host-induced gene silencing (HIGS) strategy was used to generate the transgenic eggplants expressing <italic>msp-18</italic> and <italic>msp-20</italic>, independently. Putative transformants were characterized via qRT-PCR and Southern hybridization assay. SiRNAs specific to <italic>msp-18</italic> and <italic>msp</italic>-<italic>20</italic> were also detected in the transformants via Northern hybridization assay. Transgenic expression of the RNAi constructs of <italic>msp-18</italic> and <italic>msp-20</italic> genes resulted in 43.64–69.68% and 41.74–67.30% reduction in <italic>M. incognita</italic> multiplication encompassing 6 and 10 events, respectively. Additionally, transcriptional oscillation of CWMEs documented in the penetrating and developing nematodes suggested the possible interaction among CWMEs and pioneer genes. The rapid assimilation of plant-derived carbon by invading nematodes was also demonstrated using <sup>14</sup>C isotope probing approach. Our data suggests that HIGS of <italic>msp-18</italic> and <italic>msp-20</italic>, improves nematode resistance in eggplant by affecting the steady-state transcription level of CWME genes in invading nematodes, and safeguard the plant against nematode invasion at very early stage because nematodes may become the recipient of bioactive RNA species during the process of penetration into the plant root.</p>