In:
Plant Biotechnology Journal, Wiley, Vol. 18, No. 2 ( 2020-02), p. 429-442
Abstract:
The rice root system is important for growth. The crosstalk between auxin and cytokinin mediates root initiation and elongation. However, it remains unclear how the transcriptional network upstream of the auxin and cytokinin signalling pathways determines root development. Here, we observed that the knockdown of Os NAC 2 , which encodes a NAC transcription factor, increased the primary root length and the number of crown roots. Os NAC 2 predominantly expressed in primary root tips, crown roots and lateral root primordia, implying it influences root development. Molecular analyses revealed that the expressions of auxin‐ and cytokinin‐responsive genes were affected in Os NAC 2 ‐overexpressing ( Os NAC 2‐ OX ; ON 7 and ON 11 ), RNA interference ( Os NAC 2‐ RNA i ; RNA i25 and RNA i31 ) and CRISPR /Cas9 plants. Additionally, Os NAC 2 can directly bind to the promoters of IAA inactivation‐related genes ( GH 3.6 and GH 3.8 ), an IAA signalling‐related gene ( Os ARF 25 ), and a cytokinin oxidase gene ( Os CKX 4 ). Furthermore, genetic analysis of ON 11 / osgh3.6 and RNA i31 / osckx4 homozygote confirmed that Os CKX 4 and Os GH 3.6 functioned downstream of Os NAC 2. The mRNA levels of CROWN ROOTLESS ( CRL ) genes and cyclin‐dependent protein kinase ( CDK ) genes increased in Os NAC 2‐ RNA i and Os NAC 2‐cas9 lines while reduced in Os NAC 2‐ OX lines. Thus, we describe that Os NAC 2 functions as an upstream integrator of auxin and cytokinin signals that affect CRL and CDK production to regulate cell division during root development. This novel auxin‐Os NAC 2‐cytokinin model should provide a new insight into the understanding of NAC TF s and crosstalk of auxin and cytokinin pathway, and can be potentially applied in agriculture to enhance rice yields by genetic approaches.
Type of Medium:
Online Resource
ISSN:
1467-7644
,
1467-7652
Language:
English
Publisher:
Wiley
Publication Date:
2020
detail.hit.zdb_id:
2136367-5
SSG:
12
