Chinese Bulletin of Botany ›› 2021, Vol. 56 ›› Issue (4): 404-413.DOI: 10.11983/CBB20207

• EXPERIMENTAL COMMUNICATIONS • Previous Articles     Next Articles

AtMYB77 Involves in Lateral Root Development via Regulating Nitric Oxide Biosynthesis under Drought Stress in Arabidopsis thaliana

Yongmei Che, Yanjun Sun, Songchong Lu, Lixia Hou, Xinxin Fan, Xin Liu*()   

  1. Key Lab of Plant Biotechnology in Universities of Shandong Province, Life Science College, Qingdao Agricultural University, Qingdao 266109, China
  • Received:2020-12-22 Accepted:2021-04-19 Online:2021-07-01 Published:2021-06-30
  • Contact: Xin Liu
  • About author:First author contact:

    †These authors contributed equally to this paper

Abstract: Both transcription factor MYB77 and signal molecule nitric oxide (NO) are important regulators of lateral root development. However, our understanding about the role of MYB77 and NO in the regulation of lateral root formation in plants remains elusive. This study investigated the roles and interrelation of MYB77 and NO in regulating lateral root formation under drought stress by using wild type Arabidopsis, AtMYB77 deletion mutant Atmyb77-1 and overexpression lines AtOE77-1 and AtOE77-3. The results showed that the expression of AtMYB77 was induced by drought stress. When subjected to drought stress treatment, the Atmyb77-1 mutant showed down-regulation of CYCA2;1 and CDKA;1, two genes that are related with lateral root development. Meanwhile, the number and length of lateral roots in the Atmyb77-1 mutant were significantly lower than those in wild type, while AtOE77-1 and AtOE77-3 lines displayed more and longer lateral roots. These results indicated that AtMYB77 was involved in the regulation of lateral root development under drought stress. We also showed that drought stress could increase the NO content, as well as the nitric oxide synthase (NOS) and nitrate reductase (NR) enzymes activity and gene expression in roots of Arabidopsis. Such increase in NO content, NOS and NR activities as well as related gene transcript levels were attenuated by deletion of AtMYB77 but enhanced by AtMYB77 overexpression. Exogenous NO donor sodium nitroprusside (SNP) alleviated the inhibitive effects of AtMYB77 deletion on the expressions of CYCA2;1 and CDKA;1 as well as the lateral root formation, while NO sca-vengers or synthesis inhibitors attenuate the promoting effect of AtMYB77 overexpression on lateral root growth. Taken together, these results demonstrate that AtMYB77 participates in drought-induced lateral root growth by promoting NO synthesis.

Key words: AtMYB77, NO, lateral root development, drought stress, Arabidopsis thaliana