Seasonal deviation effects foliar endophyte assemblage and diversity in Asparagus racemosus and Hemidesmus indicus

Fungal endophytes are the living symbionts which cause no apparent damage to the host tissue. The distribution pattern of these endophytes within a host plant is mediated by environmental factors. This study was carried out to explore the fungal endophyte community and their distribution pattern in Asparagus racemosus and Hemidesmus indicus growing in the study area.

Foliar endophytes were isolated for 2 years from A. racemosus and H. indicus at four different seasons (June-August, September-November, December-February, March-May). A total of 5400 (675/season/year) leaf segments harbored 38 fungal species belonging to 17 genera, 12 miscellaneous mycelia sterile from 968 isolates and 13 had yeast like growth. In A. racemosus, Acremonium strictum and Phomopsis sp.1, were dominant with overall relative colonization densities (RCD) of 7.11% and 5.44% respectively, followed by Colletotrichum sp.3 and Colletotrichum sp.1 of 4.89% and 4.83% respectively. In H. indicus the dominant species was A. strictum having higher overall RCD of 5.06%, followed by Fusarium moniliforme and Colletotrichum sp.2 with RCD of 3.83% and 3%, respectively. Further the overall colonization and isolation rates were higher during the wet periods (September-November) in both A. racemosus (92.22% and 95.11%) and H. indicus (82% and 77.11%).

Study samples treated with 0.2% HgCl₂ and 75% EtOH for 30 s and 1 min, respectively, confirmed most favorable method of isolation of the endophytes. Owing to high mean isolation and colonization rates, September-November season proved to be the optimal season for endophyte isolation in both the study plants. Assessing the bioactive potential of these endophytes, may lead to the isolation of novel natural products and metabolites.