Black pepper (Piper nigrum L.) is one of the most important crops and global demand continues to increase, giving it a high export value. However, black pepper cultivation has been seriously affected by a number of pathogenic diseases. Among them, “quick wilt” caused by Phytophthora sp., “slow decline” caused by Fusarium sp., and root-knot nematode Meloidogyne sp. have a serious negative effect on black pepper growth and productivity. There have been different chemical and biological methods applied to control these diseases, but their effectiveness has been limited. The aim of this research was to evaluate different combinations of rhizosphere bacteria and endophytic bacteria isolated from black pepper farms in the Central Highland of Vietnam for their ability to suppress pathogens and promote black pepper growth and yield. Formula 6, containing the strains Bacillus velezensis KN12, Bacillus amyloliquefaciens DL1, Bacillus velezensis DS29, Bacillus subtilis BH15, Bacillus subtilis V1.21 and Bacillus cereus CS30 exhibited the largest effect against Phytophthora and Fusarium in the soil and in the roots of black pepper. These bio-products also increased chlorophyll a and b contents, which led to a 1.5-fold increase of the photosynthetic intensity than the control formula and a 4.5% increase in the peppercorn yield (3.45 vs. 3.30 tons per hectare for the control). Our results suggest that the application of rhizosphere and endophytic bacteria is a promising method for disease control and growth-promotion of black pepper.

Despite the increasing knowledge on the importance of the intron splicing of chloroplast genes during plant growth and stress responses, identification of intron-containing chloroplast genes and determination of splice sites in chloroplast introns are still lacking. Here, we carried out a comprehensive analysis of the chloroplast genome sequences in important plants and crops, including four dicots (Arabidopsis thaliana, Coffea arabica, Nicotiana tabacum, and Panax schinseng) and four monocots (Musa acuminata, Oryza sativa, Triticum aestivum, and Zea mays). The results showed that both dicot and monocot chloroplast genomes harbor 6 intron-containing tRNAs (trnA, trnG, trnI, trnK, trnL, and trnV) and 10-12 intron-containing mRNAs (atpF, rpl2, rpl16, rps16, ndhA, ndhB, petB, petD, rpoC1, rps12, ycf3, and clpP). Notably, rpoC1 and clpP lacked introns in monocot plants, except M. acuminata. Analysis of the nucleotide sequences of chloroplast introns revealed that the 5’-splice sites, 3’-splice sites, and branch-point sites of the chloroplast introns were highly conserved among dicots and monocots. Notably, the 5’-splice sites and 3’-splice sites of the chloroplast introns were similar to those of the nuclear U12 introns, whereas the branch-point sites of the chloroplast introns were homologous to those of the nuclear U2 introns. Taken together, these results indicated that the chloroplast genomes contained strictly limited intron-containing genes with conserved splice sites, suggesting that splicing of chloroplast introns was important for chloroplast biogenesis and function in both dicot and monocot plants.

Coffee plant is one of the most important industrial crops, and the two popular cultivars, Coffea arabica and Coffea canephora, contribute to the production of almost all coffee beans around the world. Although the demand for coffee beans is continually increasing, the steady production of coffee beans is hampered by many factors, such as environmental stresses, insect pests, and diseases. Traditional breeding could be used to develop new coffee cultivars with a higher productivity under these harsh conditions, and a biotechnological approach can also be used to improve coffee plants in a relatively short period of time. To develop new coffee cultivars via a biotechnological approach, it is necessary to discover potential candidate genes and determine their functions in coffee plants. However, it is technically difficult to introduce foreign genes into coffee genome and takes long time to analyze gene function in coffee plants. To overcome these technical difficulties, the potential coffee genes could be cloned and introduced into Arabidopsis for the rapid analysis of its biological functions under harsh environmental conditions.