Research Progress on Molecular Breeding of Resistance to Disease in Pepper

Pepper originated in South America and was introduced to China in the 16th century. With high nutritional value, pepper has an important role in health care, beauty, food, medicine, violence and other industries. It becomes one of the most important vegetable crops in China. With the gradual increase of cultivation area pepper ranks the top among vegetable crops in China in this aspect. In the process of pepper production, it inevitably suffers from various diseases, causing great losses to production. It is the most economical and effective measure to control diseases through selecting disease-resistant varieties, although the chemical control methods and agricultural control measures can reduce the harm to a certain extent. With the development of molecular biology, the combination of molecular breeding and conventional breeding methods for disease resistance is a direction of future breakthroughs. In recent years, great progress has been made in the molecular breeding of pepper disease resistance, especially, the molecular mechanism of disease resistance. Molecular breeding mainly includes two parts: one is marker-assisted breeding, and the other is creating disease-resistant breeding materials by means of genetic engineering. In marker-assisted breeding, molecular markers must be found first. Molecular markers are divided into gene markers, markers obtained by linkage analysis in segregation populations, and markers gotten by association analysis through sequencing of a large number of materials. The premise of genetic engineering is to isolate and obtain disease resistance genes, and then introduce them into pepper breeding materials with good economic traits, or mutate negatively regulated genes through gene editing technology or gene silencing technology to improve disease resistance of plants. In this paper, molecular markers and marker-assisted selection, molecular mechanism of disease resistance and disease-resistant germplasm (resistance to virus, bacterial wilt and Phytophthora capsici) obtained by genetic engineering technology are comprehensively introduced, and the development trend and research focus in the future are prospected.