NAC transcription factor ONAC066 positively regulates disease resistance by suppressing the ABA signaling pathway in rice
Qing Liu1，Shijuan
Yan2，Wenjie
Huang2 ，Jianyuan Yang3 ，Jingfang
Dong1， Shaohong Zhang1 ， Junliang Zhao1 ，Tifeng Yang1 ， Xingxue Mao1 ， Xiaoyuan Zhu3 ，Bin Liu1
Plant Molecular
Biology
Abstract
Key
message This is the first
time to dissect the mechanism of NACs-mediated disease resistance in plants
using metabolomic approach and discover the involvement of ABA signaling
pathway in NACs-mediated disease resistance.
Abstract NAC transcription factors have been validated as important regulators in stress
responses, but their molecular mechanisms in plant disease resistance are still
largely unknown. Here we report that the NAC gene ONAC066 (LOC_Os01g09550) is significantly activated by rice blast
infection. ONAC066 is ubiquitously
expressed and this protein is localized in the nucleus. Overexpression of ONAC066 quantitatively enhances
resistance to blast disease and bacterial blight in rice. The transcript levels
of PR genes are also dramatically induced in ONAC066 overexpressing plants. Exogenous abscisic acid (ABA) strongly
activates the transcription of ONAC066 in rice. Further analysis shows that overexpression of ONAC066 remarkably suppresses the expression of ABA-related genes,
whereas there are no obvious differences for salicylic acid (SA) and jasmonic
acid (JA)-related genes between wild-type and ONAC066 overexpressing plants. Consistently, lower endogenous ABA
levels are identified in ONAC066 overexpressing plants compared with wild-type plants before and after blast inoculation,
while no significant differences are observed for the SA and JA levels. Yeast
one-hybrid assays demonstrate that ONAC066 directly binds to the promoters of LIP9 and NCED4 to modulate their expression.
Moreover, the metabolomics study reveals that the ONAC066 overexpressing plants accumulated higher contents of
soluble sugars and amino acids both before and after pathogen attack, when
compared to wild-type plants. Taken together, our results suggest that ONAC066 positively regulates rice
resistance to blast and bacterial blight, and ONAC066 exerts its functions on disease resistance by modulating of
ABA signaling pathway, sugars and amino acids accumulation in rice.
