A new canker on Gleditsia sinensis caused by Thyronectria austroamericana in China

Abstract

Gleditsia sinensis is a medicinal plant that brings an annual economic value of nearly 400 million to Song County, Henan Province, China. From 2021 to 2022, a canker disease was observed on the branches of G. sinensis. The diseased plants often displayed symptoms of wilting, yellowing, early leaf drop and total plant death. The incidence of canker on G. sinensis was estimated at 20%–40% for the years 2021, 2022 and 2023, with 50% of the infected plants ultimately perishing. The putative pathogen was isolated from symptomatic G. sinensis branches. Thyronectria austroamericana was identified as the causal agent by using morphology and molecular phylogeny of multi-loci (alpha-actin (act), internal transcribed spacer (ITS) region, large nuclear ribosomal RNA subunit (LSU), translation elongation factor 1-alpha (tef1), and β-tubulin (tub2) sequence data. In vitro and field inoculation experiments showed that the fungus could produce canker symptoms in G. sinensis which is similar to those observed in the field. The putative pathogen was re-isolated and Koch's postulates were fulfilled. This study provides the first report of T. austroamericana causing G. sinensis canker disease in China. Furthermore, these results will contribute to the knowledge of the G. sinensis canker disease.