Transcriptome and gene family analyses reveal mechanisms of blight resistance in rabbiteye blueberry.

INTRODUCTION

Blueberry branch blight is a severe plant disease primarily caused by .

METHODS

In this study, one-year-old branches of two rabbiteye blueberries (): resistant Tifblue ('TF') and susceptible Climax ('DF') were selected as experimental materials, the physiological parameters of two cultivars pre- and post- inoculation. Transcriptomic analysis and comprehensive gene family characterization were conducted to examine the differential gene expression.

RESULTS

The results indicated that 'TF' exhibited higher lignin content and activity levels of peroxidase enzymes (POD), phenylalanine ammonia-lyase (PAL), and cinnamyl alcohol dehydrogenase (CAD) compared to 'DF'. RNA-sequence analysis revealed that at 24 hours post-inoculation, there were 136 and 121 differentially expressed genes related to lignin synthesis in 'TF' and 'DF', respectively. The analysis of these DEGs revealed that numerous of key enzyme genes in lignin synthesis pathways, including , , , , , and were annotated. Additionally, we characterized the gene family, identifying 93 coding genes at the blueberry genome level, which were classified into four subgroups. Most gene promoters contained response elements associated with plant stress resistance pathways. QRT- PCR experiments demonstrated that the expression levels of and genes were significantly upregulated at 24 hours post-inoculation.

DISCUSSION

These findings suggest that enhance lignin synthesis, improve the resistance of blueberries to shoot blight, and provide novel insights into the defense mechanisms of blueberries against .