OsGRF6-OsYUCCA1/OsWRKY82 Signaling Cascade Upgrade Grain Yield and Bacterial Blight Resistance in Rice.

Area of Science:

• Plant genetics and breeding
• Crop pathology
• Molecular biology

Background:

• Bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), severely restricts global rice production.
• Developing disease resistance in rice often leads to reduced yield potential, posing a challenge for sustainable agriculture.
• Identifying genes that simultaneously enhance disease resistance and yield is crucial for crop improvement.

Purpose of the Study:

• To investigate the role of OsGRF6 in improving rice bacterial blight resistance and yield.
• To elucidate the molecular mechanism by which OsGRF6 influences disease resistance and crop performance.
• To identify superior haplotypes of OsGRF6 for breeding disease-resistant and high-yield rice varieties.

Main Methods:

• Generation of transgenic rice overexpressing OsGRF6.
• Inoculation of transgenic and wild-type rice with Xanthomonas oryzae pv. oryzae (Xoo).
• Quantitative analysis of lesion length and yield parameters.
• Promoter binding assays and gene expression analysis of target genes (OsYUCCA1, OsWRKY82).
• Haplotypic and evolutionary analysis of OsGRF6.

Main Results:

• Overexpression of OsGRF6 significantly reduced lesion lengths in rice after Xoo inoculation compared to wild-type.
• OsGRF6 directly binds to the promoters of OsYUCCA1 and OsWRKY82, upregulating their transcription.
• Transgenic lines overexpressing OsGRF6 exhibited enhanced bacterial blight resistance and increased yield potential.
• Haplotypic analysis identified OsGRF6^Hap4 as a superior haplotype that enhances transcriptional activity, contributing to disease resistance and yield.

Conclusions:

• OsGRF6 is a valuable gene for simultaneously improving rice bacterial blight resistance and yield.
• The mechanism involves OsGRF6-mediated upregulation of OsYUCCA1 and OsWRKY82.
• Superior haplotypes like OsGRF6^Hap4 offer a promising strategy for breeding enhanced rice cultivars.
• This study provides a foundation for understanding the synergistic regulation of yield and disease resistance in rice.