Genome-wide characterization and expression of the TLP gene family associated with Colletotrichum gloeosporioides inoculation in Fragaria × ananassa

Background: Colletotrichum gloeosporioides, a soil-borne fungal pathogen, causes significant yield losses in many plants, including cultivated strawberry (Fragaria × ananassa, 2n = 8x = 56). Thaumatin-like proteins (TLPs) are a large and complex family of proteins that play a vital role in plant host defense and other physiological processes.

Methods: To enhance our understanding of the antifungal activity of F. × ananassa TLPs (FaTLP), we investigated the genome-wide identification of FaTLP gene families and their expression patterns in F. × ananassa plants upon pathogen infection. Moreover, we used RNA sequencing (RNA-seq) to detect the differences in the expression patterns of TLP genes between different resistant strawberry cultivars in response to C. gloeosporioides infection.

Results: In total, 76 TLP genes were identified from the octoploid cultivated strawberry genome with a mean length of 1,439 bp. They were distributed on 24 F. × ananassa chromosomes. The FaTLP family was then divided into ten groups (Group I-X) according to the comparative phylogenetic results. Group VIII contained the highest number of TLP family genes. qRT-PCR analysis results indicated that FaTLP40, FaTLP41, FaTLP43, FaTLP68, and FaTLP75 were upregulated following C. gloeosporioides infection in the resistant octoploid strawberry.

Conclusions: The data showed some differences in TLP gene expression patterns across different resistant strawberry cultivars, as well as faster TLP defense responses to pathogenic fungi in resistant cultivars. This study will aid in the characterization of TLP gene family members found in octoploid strawberries and their potential biological functions in plants' defenses against pathogenic fungi.