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Members of Didymellaceae have a wide geographical distribution throughout different ecosystems, and most species are associated with fruit, leaf, stem and root diseases of land plants. However, species that occur in aquatic plants are not clearly known. During a survey of the diversity of endophytes in aquatic plants in Yunnan, Sichuan, and Guizhou provinces, we obtained 51 isolates belonging to Didymellaceae based on internal transcribed spacer region (ITS) sequences. Further, the phylogenetic positions of these isolates were determined by combined sequences composed of ITS, partial large subunit nrRNA gene (28S nrDNA; LSU), RNA polymerase II second largest subunit (rpb2) and partial beta-tubulin gene (tub2). Combining morphological characteristics and multi-locus phylogenetic analyses, two new varieties belong to Boeremia and 12 new species distributed into seven genera were recognized from 51 isolates, i.e., Cumuliphoma, Didymella, Dimorphoma, Ectophoma, Leptosphaerulina, Remotididymella, and Stagonosporopsis. Among these species, only one species of Stagonosporopsis and two species of Leptosphaerulina show teleomorphic stages on OA, but have no anamorphic state. Each new species is described in detail, and the differences between new species and their phylogenetically related species are discussed here. The high frequency of new species indicates that aquatic plants may be a special ecological niche which highly promotes species differentiation. At the same time, the frequent occurrence of new species may indicate the need for extensive investigation of fungal resources in those aquatic environments where fungal diversity may be underestimated.

Ageratina adenophora is one of the most invasive weeds in China. Following an outbreak in Yunnan in the 1960s, A. adenophora has been spreading in Southwest China at tremendous speed. Previous research indicated A. adenophora contained many Colletotrichum species as endophytes. In this study, we investigated the diversity of Colletotrichum in healthy and diseased leaves of the invasive plant A. adenophora and several surrounding crops in Yunnan, Guangxi, and Guizhou provinces in China, and obtained over 1000 Colletotrichum strains. After preliminary delimitation using the internal transcribed spacer region (ITS) sequences, 44 representative strains were selected for further study. Their phylogenetic positions were determined by phylogenetic analyses using combined sequences of ITS, actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-tubulin (TUB2). Combined with morphological characteristics, 14 new Colletotrichum species were named as C. adenophorae, C. analogum, C. cangyuanense, C. dimorphum, C. gracile, C. nanhuaense, C. nullisetosum, C. oblongisporum, C. parvisporum, C. robustum, C. simulanticitri, C. speciosum, C. subhenanense, and C. yunajiangense.

Colletotrichum species are plant pathogens, saprobes, and endophytes in many economically important hosts. Many studies have investigated the diversity and pathogenicity of Colletotrichum species in common ornamentals, fruits, and vegetables. However, Colletotrichum species occurring in aquatic plants are not well known. During the investigation of the diversity of endophytic fungi in aquatic plants in southwest China, 66 Colletotrichum isolates were obtained from aquatic plants there, and 26 of them were selected for sequencing and analyses of actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the internal transcribed spacer (ITS) region, and β-tubulin (TUB2) genomic regions. Based on morphological characterization and multi-locus phylogenetic analyses, 13 Colletotrichum species were recognized, namely, C. baiyuense sp. nov., C. casaense sp. nov., C. demersi sp. nov., C. dianense sp. nov., C. fructicola, C. garzense sp. nov., C. jiangxiense, C. karstii, C. philoxeroidis sp. nov., C. spicati sp. nov., C. tengchongense sp. nov., C. vulgaris sp. nov., C. wuxuhaiense sp. nov. Two species complexes, the C. boninense species complex and C. gloeosporioides species complex, were found to be associated with aquatic plants. Pathogenicity tests revealed a broad diversity in pathogenicity and aggressiveness among the eight new Colletotrichum species.

During the investigation of endophytic fungi diversity in aquatic plants and the fungal diversity in soil in southwest China, we obtained 208 isolates belonging to Trichoderma, including 28 isolates as endophytes from aquatic plants and 180 isolates as saprobes from soil, respectively. Finally, 23 new species of Trichoderma are recognized by further studies. Their phylogenetic positions are determined by sequence analyses of the combined partial sequences of translation elongation factor 1-alpha (tef1) and gene encoding of the second largest nuclear RNA polymerase subunit (rpb2). The results revealed that the 23 new species are distributed in nine known clades. The morphology and culture characteristics are observed, described and illustrated in detail. Distinctions between the new species and their close relatives were compared and discussed. These include: Trichoderma achlamydosporum, T. amoenum, T. anaharzianum, T. anisohamatum, T. aquatica, T. asiaticum, T. asymmetricum, T. inaequilaterale, T. inconspicuum, T. insigne, T. obovatum, T. paraviride, T. pluripenicillatum, T. propepolypori, T. pseudoasiaticum, T. pseudoasperelloides, T. scorpioideum, T. simile, T. subazureum, T. subuliforme, T. supraverticillatum, T. tibetica, and T. uncinatum.

Starch is promising candidate material for enhancing the catalytic activity of α-amylase during the crosslinking process. To help meet industrial needs, here we tested the influence of bovine serum albumin (BSA) and starch on the performance of crosslinked α-amylase aggregates (CLEA), α-amylase-prepared as CLEA with starch (CLEA-S), and BSA (CLEA-BSA). Our results showed that the activities of CLEA, CLEA-S, and CLEA-BSA were 1.1-, 1.0-, and 0.74-fold higher than the free α-amylase, respectively. The stability of the immobilized enzyme slightly changed. After immobilization, the enzyme increased its pH and temperature ranges with the optimal pH values of 5.5, 7.5, 5.5, respectively for CLEA, CLEA-S, and CLEA-BSA, and an upper temperature limit of 50 °C for all three immobilized forms. Among the three immobilized forms, the CLEA-S was the most thermostable, losing only 3% of its initial activity during 390 min incubation at 50 °C. Our microscopic observations of CLEA-S showed that porous structures were formed and such structures could help substance diffusion. In addition, there was excellent affinity between CLEA-S and the substrate. The results suggest that CLEA-S have great potential for industrial application, including for use in starch-based alcohol fermentation.