OsFBN6 Enhances Brown Spot Disease Resistance in Rice

Area of Science:

• Plant Pathology
• Molecular Biology
• Genetics

Background:

• Brown spot (BS) disease, caused by Cochliobolus miyabeanus, significantly reduces rice yield and quality.
• Fibrillins (FBNs) are involved in plant stress responses, with OsFBN1 and OsFBN5 linked to rice disease resistance and the Jasmonic Acid (JA) pathway.
• The role of OsFBN6 in rice disease resistance was previously uncharacterized.

Purpose of the Study:

• To investigate the role of OsFBN1, OsFBN5, and OsFBN6 in rice resistance to brown spot disease.
• To explore the involvement of the JA pathway in rice's response to brown spot.
• To develop genetic markers for screening brown spot-resistant rice varieties.

Main Methods:

• Gene expression analysis of OsFBN1, OsFBN5, OsFBN6, and OsAOS2 following C. miyabeanus infection and methyl jasmonate (meJA) treatment.
• Haplotype analysis of FBN genes in relation to brown spot infection scores.
• Construction and evaluation of OsFBN6 overexpression lines.
• Development of genetic markers based on whole-genome sequencing and haplotype analysis.

Main Results:

• OsAOS2 gene expression was significantly regulated by C. miyabeanus infection and meJA treatment, indicating JA pathway involvement in BS resistance.
• OsFBN1, OsFBN5, and OsFBN6 exhibited distinct gene expression patterns under stress conditions.
• Haplotype analysis revealed significant associations between FBN gene haplotypes and BS infection scores, with OsFBN6 showing strong significance.
• OsFBN6 overexpression lines demonstrated enhanced resistance to brown spot compared to wild-type rice.

Conclusions:

• OsFBN6 positively regulates rice resistance to brown spot disease.
• The JA pathway plays a crucial role in rice's defense against C. miyabeanus.
• Developed genetic markers, specifically the Caps marker at Chr4_30690229, can facilitate the selection of BS-resistant rice varieties in breeding programs.