AUTHOR=Rashid Md. Harun-Or- , Khan Ajmal , Hossain Mohammad T. , Chung Young R. 

TITLE=Induction of Systemic Resistance against Aphids by Endophytic Bacillus velezensis YC7010 via Expressing PHYTOALEXIN DEFICIENT4 in Arabidopsis

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00211

DOI=10.3389/fpls.2017.00211

ISSN=1664-462X

ABSTRACT=<p>Aphids are the most destructive insect pests. They suck the sap and transmit plant viruses, causing widespread yield loss of many crops. A multifunctional endophytic bacterial strain <italic>Bacillus velezensis</italic> YC7010 has been found to induce systemic resistance against bacterial and fungal pathogens of rice. However, its activity against insects attack and underlying cellular and molecular defense mechanisms are not elucidated yet. Here, we show that root drenching of <italic>Arabidopsis</italic> seedlings with <italic>B. velezensis</italic> YC7010 can induce systemic resistance against green peach aphid (GPA), <italic>Myzus persicae</italic>. Treatment of bacterial suspension of <italic>B. velezensis</italic> YC7010 at 2 × 10<sup>7</sup> CFU/ml to <italic>Arabidopsis</italic> rhizosphere induced higher accumulation of hydrogen peroxide, cell death, and callose deposition in leaves compared to untreated plants at 6 days after infestation of GPA. Salicylic acid, jasmonic acid, ethylene, and abscisic acid were not required to confer defense against GPA in <italic>Arabidopsis</italic> plants treated by <italic>B. velezensis</italic> YC7010. Bacterial treatment with <italic>B. velezensis</italic> YC7010 significantly reduced settling, feeding and reproduction of GPA on <italic>Arabidopsis</italic> leaves via strongly expressing senescence-promoting gene <italic>PHYTOALEXIN DEFICIENT4</italic> (<italic>PAD4</italic>) while suppressing <italic>BOTRYTIS-INDUCED KINASE1</italic> (<italic>BIK1</italic>). These results indicate that <italic>B. velezensis</italic> YC7010-induced systemic resistance to the GPA is a hypersensitive response mainly dependent on higher expression of <italic>PAD4</italic> with suppression of <italic>BIK1</italic>, resulting in more accumulation of hydrogen peroxide, cell death, and callose deposition in <italic>Arabidopsis</italic>.</p>