Critical Secondary Metabolites Confer the Broad-Spectrum Pathogenic Fungi Resistance Property of a Marine-Originating Streptomyces sp. HNBCa1.

Obtaining a microorganism strain with a broad-spectrum resistance property and highly efficient antifungal activity is important to the biocontrol strategy. Herein, a marine Streptomyces sp. HNBCa1 demonstrated a broad-spectrum resistance to 17 tested crop pathogenic fungi and exhibited a high biocontrol efficiency against mango anthracnose and banana fusarium wilt. To uncover the critical bioactive secondary metabolites basis, genome assembly and annotation, metabolomic analysis, and a semipreparative HPLC-based activity-guide method were employed. Finally, geldanamycin and ectoine involved in codifferential secondary metabolites were also found to be related to biosynthetic gene clusters in the genome of HNBCa1. Reblastatin and geldanamycin were uncovered in response to broad-spectrum resistance to the 17 crop pathogenic fungi. Our results suggested that reblastatin and geldanamycin were critical to maintaining the broad-spectrum resistance property and highly efficient antifungal activity of HNBCa1, which could be further developed as a biological control agent to control crop fungal diseases.

Natural Products and Biological Activity from Actinomycetes Associated with Marine Algae.

Marine natural products have been recognized as the most promising source of bioactive substances for drug discovery research. This review illustrates the diversity of culturable actinobacteria associated with marine algae, their bioactivity and metabolites, and approaches to their isolation and determination of their biological properties. Furthermore, actinobacteria associated with marine algae are presented as a new subject for an extensive investigation to find novel and active natural products, which make them a potentially rich and innovative source for new drug development deserving more attention and exploration.

Metabolomic profiles and health-promoting functions of Camellia drupifera mature-seeds were revealed relate to their geographical origins using comparative metabolomic analysis and network pharmacology approach.

To insight into the chemical components and their health-promoting function of Camellia drupifera mature-seeds (CMS) in Hainan and Liangguang, UPLC-MS/MS- and HS-SPME/GC-MS-based metabolomic analyses and network pharmacology approaches were combined preformed to Camellia drupifera mature-seeds samples (CMSSs). Totally, 1057 metabolites were identified, of which 76 and 99 metabolites were annotated as key active ingredients in Traditional Chinese Medicines and the active pharmaceutical ingredients for seven human disease-resistance, respectively. Comparative analysis revealed different metabolomic profiles of CMSSs from Hainan and Liangguang. KEGG annotation and enrichment analysis showed secondary metabolic pathways, especially "flavone and flavonol biosynthesis", were played important roles. Finally, 22 metabolites that only detected in CMSSs from Hainan or Liangguang were explored as potential indicators to separate CMS from Hainan out of Liangguang. Our findings enhanced the understanding of chemical compositions of CMS and provided valuable information for the healthy development of oil-tea Camellia industry in Hainan.

Genetic relationships and low diversity among the tea-oil Camellia species in Sect. Oleifera, a bulk woody oil crop in China.

Tea-oil Camellia is one of the four woody oil crops in the world and has high ecological, economic and medicinal values. However, there are great differences in the classification and merging of tea-oil Camellia Sect. Oleifera species, which brings difficulties to the innovative utilization and production of tea-oil Camellia resources. Here, ISSR, SRAP and chloroplast sequence markers were analyzed in 18 populations of tea-oil Camellia Sect. Oleifera species to explore their phylogenetic relationships and genetic diversity. The results showed that their genetic diversity were low, with mean H and π values of 0.16 and 0.00140, respectively. There was high among-population genetic differentiation, with ISSR and SRAP markers showing an Fst of 0.38 and a high Nm of 1.77 and cpDNA markers showing an Fst of 0.65 and a low Nm of 0.27. The C. gauchowensis, C. vietnamensis and Hainan Island populations formed a single group, showing the closest relationships, and supported being the same species for them with the unifying name C. drupifera and classifying the resources on Hainan Island as C. drupifera. The tea-oil Camellia resources of Hainan Island should be classified as a special ecological type or variety of C. drupifera. However, cpDNA marker-based STRUCTURE analysis showed that the genetic components of the C. osmantha population formed an independent, homozygous cluster; hence, C. osmantha should be a new species in Sect. Oleifera. The C. oleifera var. monosperma and C. oleifera populations clustered into two distinct clades, and the C. oleifera var. monosperma populations formed an independent cluster, accounting for more than 99.00% of its genetic composition; however, the C. oleifera populations contained multiple different cluster components, indicating that C. oleifera var. monosperma significantly differs from C. oleifera and should be considered the independent species C. meiocarpa. Haplotype analysis revealed no rapid expansion in the tested populations, and the haplotypes of C. oleifera, C. meiocarpa and C. osmantha evolved from those of C. drupifera. Our results support the phylogenetic classification of Camellia subgenera, which is highly significant for breeding and production in tea-oil Camellia.

Efficient expression and function of a receptor-like kinase in wheat powdery mildew defence require an intron-located MYB binding site.

The LRK10-like receptor kinases (LRK10L-RLKs) are ubiquitously present in higher plants, but knowledge of their expression and function is still limited. Here, we report expression and functional analysis of TtdLRK10L-1, a typical LRK10L-RLK in durum wheat (Triticum turgidum L. ssp. durum). The introns of TtdLRK10L-1 contained multiple kinds of predicted cis-elements. To investigate the potential effect of these cis-elements on TtdLRK10L-1 expression and function, two types of transgenic wheat lines were prepared, which expressed a GFP-tagged TtdLRK10L-1 protein (TtdLRK10L-1:GFP) from the cDNA or genomic DNA (gDNA) sequence of TtdLRK10L-1 under the native promoter. TtdLRK10L-1:GFP expression was up-regulated by the powdery mildew pathogen Blumeria graminis f. sp. tritici (Bgt) in both types of transgenic plants, with the scale of the elevation being much stronger in the gDNA lines. Both types of transgenic plants exhibited enhanced resistance to Bgt infection relative to wild type control. Notably, the Bgt defence activated in the gDNA lines was significantly stronger than that in the cDNA lines. Further analysis revealed that a putative MYB transcription factor binding site (MYB-BS, CAGTTA) located in TtdLRK10L-1 intron I was critical for the efficient expression and function of TtdLRK10L-1 in Bgt defence. This MYB-BS could also increase the activity of a superpromoter widely used in ectopic gene expression studies in plants. Together, our results deepen the understanding of the expression and functional characteristics of LRK10L-RLKs. TtdLRK10L-1 is likely useful for further dissecting the molecular processes underlying wheat defence against Bgt and for developing Bgt resistant wheat crops.

The alternative splicing of EAM8 contributes to early flowering and short-season adaptation in a landrace barley from the Qinghai-Tibetan Plateau.

KEY MESSAGE: The early flowering of Lalu was determined to be due to a novel spontaneous eam8 mutation, which resulted in intron retention and the formation of a putative truncated protein. Barley is a staple crop grown over an extensive area in the Qinghai-Tibetan Plateau. Understanding the genetic mechanism for its success in a high altitude is important for crop improvement in marginal environments. Early flowering is a critical adaptive trait that strongly influences reproductive fitness in a short growing season. Loss-of-function mutations at the circadian clock gene EARLY MATURITY 8 (EAM8) promote rapid flowering. In this study, we identified a novel, spontaneous recessive eam8 mutant with an early flowering phenotype in a Tibetan barley landrace Lalu, which is natively grown at a high altitude of approximately 4000 m asl. The co-segregation analysis in a F2 population derived from the cross Lalu (early flowering) × Diqing 1 (late flowering) confirmed that early flowering of Lalu was determined to be due to an allele at EAM8. The eam8 allele from Lalu carries an A/G alternative splicing mutation at position 3257 in intron 3, designated eam8.l; this alternative splicing event leads to intron retention and a putative truncated protein. Of the 134 sequenced barley accessions, which are primarily native to the Qinghai-Tibet Plateau, three accessions carried this mutation. The eam8.l mutation was likely to have originated in wild barley due to the presence of the Lalu haplotype in H. spontaneum from Tibet. Overall, alternative splicing has contributed to the evolution of the barley circadian clock and in the short-season adaptation of local barley germplasm. The study has also identified a novel donor of early-flowering barley which will be useful for barley improvement.