Loss of OsSPL8 function confers improved resistance to glufosinate and
abiotic stresses in rice
Abstract
Weeds are among the most significant factors contributing to decreases
in crop yield and quality. Glufosinate, a nonselective, broad-spectrum
herbicide, has been extensively utilized for weed control in recent
decades. However, crops are usually sensitive to glufosinate. Therefore,
the development of glufosinate-resistant crops is crucial for effective
weed management in agriculture. In this study, we characterized a
SQUAMOSA promoter-binding-like (SPL) factor, OsSPL8, which acts as a
negative regulator of glufosinate resistance by inhibiting the
transcription of OsGS1;1 and OsGS2 and consequently
reducing GS activity. Furthermore, the loss of OsSPL8 function
enhanced tolerance to drought and salt stresses. Transcriptomic
comparisons between the gar18-3 mutant and wild type revealed
that OsSPL8 largely downregulates stress-responsive genes and
upregulates growth-related genes. We demonstrated that OsSPL8 directly
regulates OsOMTN6 and OsNAC17, which influence drought
tolerance. Additionally, OsSPL8 directly represses the expression of
salt stress tolerance-related genes such as OsHKT1.1 and
OsTPP1. Collectively, our results demonstrate that OsSPL8 is a
negative regulator of both glufosinate resistance and abiotic stress
tolerance.