AUTHOR=You Jia , Pan Fengjuan , Wang Shuo , Wang Yu , Hu Yanfeng 

TITLE=FMRFamide-Like Peptide 22 Influences the Head Movement, Host Finding, and Infection of Heterodera glycines

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.673354

DOI=10.3389/fpls.2021.673354

ISSN=1664-462X

ABSTRACT=<p>The FMRFamide-like peptides (FLPs) represent the largest family of nematode neuropeptides and are involved in multiple parasitic activities. The immunoreactivity to FMRFamide within the nervous system of <italic>Heterodera glycines</italic>, the most economically damaging parasite of soybean [<italic>Glycine max</italic> L. (Merr)], has been reported in previous research. However, the family of genes encoding FLPs of <italic>H. glycines</italic> were not identified and functionally characterized. In this study, an FLP encoding gene <italic>Hg-flp-22</italic> was cloned from <italic>H. glycines</italic>, and its functional characterization was uncovered by using <italic>in vitro</italic> RNA interference and application of synthetic peptides. Bioinformatics analysis showed that <italic>flp-22</italic> is widely expressed in multiple nematode species, where they encode the highly conserved KWMRFamide motifs. Quantitative real-time (qRT)-PCR results revealed that <italic>Hg-flp-22</italic> was highly expressed in the infective second-stage juveniles (J2s) and adult males. Silencing of <italic>Hg-flp-22</italic> resulted in the reduced movement of J2s to the host root and reduced penetration ability, as well as a reduction in their subsequent number of females. Behavior and infection assays demonstrated that application of synthetic peptides Hg-FLP-22b (TPQGKWMRFa) and Hg-FLP-22c (KMAIEGGKWVRFa) significantly increased the head movement frequency and host invasion abilities in <italic>H. glycines</italic> but not in <italic>Meloidogyne incognita</italic>. In addition, the number of <italic>H. glycines</italic> females on the host roots was found to be significantly higher in Hg-FLP-22b treated nematodes than the ddH<sub>2</sub>O-treated control J2s. These results presented in this study elucidated that <italic>Hg-flp-22</italic> plays a role in regulating locomotion and infection of <italic>H. glycines</italic>. This suggests the potential of FLP signaling as putative control targets for <italic>H. glycines</italic> in soybean production.</p>