Endophytic fungi have been explored from various plant sources for their industrial potential. Therefore, researchers focused on terrestrial plants for endophytic fungi. In this context, the present study plants the diversity of endophytic fungi associated with Tradescantia pallida, Zea mays, and Trifolium alexandrinum has been explored. Aspergillus, Penicillium, and Ganoderma species recovered highest from the stem of Tradescantia palida. Fusarium was dominant in the stem and leaf of Zea mays, Penicillium, Aspergillus, Ganoderma, Cladosporium, Fusarium, and Alternaria were recovered from the Trifolium alexandrium. This finding suggests that Aspergillus is most commonly associated with plants endophytes. These findings are similar to previous reports by other authors . However, most dominating fungal endophytes belonging to the genus Fusarium, Sarocladium, Aspergillus, and Penicillium are not tissue-specific .
The diversity index is a quantitative indicator that measures the number of different species and the degree of distribution of individuals among those species. The Shannon diversity index (H) is commonly used to characterize species diversity in a community. The Shannon index in Tradescantia pallida is highest in leaves. These findings are similar to the results of Choudhary et al. , in which they also reported the highest Shannon index in leaves. While in Zea mays and Trifolium alexandrinum, it is highest in the stem which is comparable with previous studies [18, 26]. Simpson’s diversity index tells us about species dominance. It considers both the number of species present and their relative abundance. Simpson’s diversity index (species dominance) is a measure of diversity that takes into account the number of species present, as well as the relative abundance of each species. The diversity of species increases as the richness and evenness increase. Its value (D) ranges between 0 and 1, where 1 represents infinite diversity and 0 represents no diversity. The Simpson’s index was highest in the case of Zea mays while Menhinick’s index was highest in roots of Trifolium alexandrinum. Species riches are indicated by Menhinick’s index. As per our knowledge, no comparative data is available on the endophytic diversity of the above plants taken for the study. When we compared the diversity with other plants the results are comparable. Li et al.  reported that in the root, the fungal richness was significantly higher in Salsola nitraria other plants. Furthermore, the fungal richness was significantly higher in roots than in stems. Moreover, in recent times, the diversity analysis of fungal endophytes has been performed by several authors and revealed the discovery of new species producing novel metabolites. Diversity analysis is also helpful in understanding the role of endophytes in ecosystems [28, 29].
Among the various microbial enzymes available, starch processing enzymes are one of the prominent groups applied in processes like brewing, baking, and pharmaceuticals. Amylases are the group of enzymes that are generally used for the processing of starch [30, 31]. The starch processing enzymes are classified into four different categories which include exoamylases, endoamylase, transferases, and debranching enzymes. Among the different hydrolyzing enzymes, the α-Amylases and pullulanase are the more versatile enzymes used in the industrial sector and their contribution is about 25% of the whole enzyme market . These enzymes act randomly on starches, glycogen, and oligosaccharides to yield-reducing sugar. Pullulanase is the significant industrial group in the 13 glycosyl hydrolases category, known as the α-amylases family [8, 9]. They hydrolyze the glycosidic bonds in the starch during the saccharification process and yield glucose, maltose, and maltotriose syrups. These products have found their significant applications in food and other related industries. Being a member of starch hydrolyzing enzymes, pullulanase hydrolyzes both α-1,6 and α-1,4 bond in pullulan and on other carbohydrates [33,34,35]. Therefore, the endophytes were screened for their pullulanase and amylase-producing capabilities. The recovery of pullulanase-producing endophytic fungi was very less. But the importance of pullulanase is high as compared to amylase because it has both α-1,6 and α-1,4 hydrolyzing ability. In SSF using rice bran (agro-waste) as substrate, a good yield was recovered and merit future interest for scale up the process.
Based on colony morphology, spore chain morphology, and ITS sequence analysis, the isolates BHU-25 and BHU-46 were identified as Penicillium sp. and Aspergillus species, respectively. Waqas et al.  reported Penicillium and Aspergillus species from tissues of sunflower (Helianthus annuus L.). Endophytic fungi like Synnematous sp., Nodilusporium sp., and Acremonium sp. have reported starch degrading enzymes [37, 38] reported forty-four endophytic fungal strains belonging to genus Penicillium, Cladosporium, Monodictys, Phoma, Tetraploa, and Acremonium, producing enzymes of industrial importance. However, pullulanase-producing endophytic fungi have not been reported so far.