Optimized nitrogen management enhances lodging resistance of rice and its morpho-anatomical, mechanical, and molecular mechanisms
Junfeng
Pan1,2,4, JunliangZhao1,2,4, Yanzhuo Liu1,2,
Nongrong Huang1,2, KaTian1,2, Farooq Shah3,
Kaiming Liang1,2, XuhuaZhong1,2* & Bin Liu1,2*
Scientific
Reports
Abstract
Increasing
evidence shows that improved nitrogen management can enhance lodging resistance
and lower internodes play a key role in
the lodging resistance of rice. However, little is known about the cellular and molecular mechanisms
underlying the enhanced lodging resistance under improved nitrogen management. In the present study, two
rice varieties, with contrasting lodging resistance, were grown under optimized N management (OPT)
and farmers’ fertilizer practices. Under OPT, the lower internodes of both cultivars were
shorter but the upper internodes were longer, while both culm diameter and wall thickness of lower
internodes were dramatically increased. Microscopic examination showed that the culm wall of lower internodes
under OPT contained more sclerenchyma cells beneath epidermis and vascular bundle sheath. The
genome-wide gene expression profling revealed that transcription of genes encoding cell wall
loosening factors was down-regulated while transcription of genes participating in lignin and starch
synthesis was up-regulated under OPT, resulting in inhibition of longitudinal growth, promotion in transverse
growth of lower internodes and enhancement of lodging resistance. This is the frst comprehensive
report on the morpho-anatomical, mechanical, and molecular mechanisms of lodging resistance of rice under
optimized N management.
