Biology and control of Pectobacterium in potato

Abstract

Pectobacterium species cause soft rot, blackleg, and stem rot in potato and a wide range of other vegetable crops and ornamental plants. Diseases caused by Pectobacterium are controlled mainly through use of healthy planting material, sanitation and copper sprays. Environmental factors, such as temperature, moisture and soil oxygen concentration, have a large effect on development of diseases caused by Pectobacterium and disease incidence can be unpredictable. The pathogen is spread by various mechanisms including water, seed, equipment and insects. Little is understood about plant resistance to soft rot bacterial pathogens and no commercial potato cultivars are resistant to soft rot, although some have tolerance and some wild potato species are resistant. Pectobacterium is a diverse genus, with multiple species capable of infecting potato. Multiple Pectobacterium species may be found in the same field and even on the same plant. Pectobacterium strains vary in aggressiveness and the virulence genes they encode but there are many commonalities across the genus. Over the past decade, genomic studies have provided new insights into Pectobacterium biology. For example, some Pectobacterium strains may elicit plant cell death to promote disease in leaves. Strains of the pathogen also produce an orange pigment and volatile compounds that increase virulence and that may act as insect kairomones. Recent work with a supervised machine learning program has identified several novel target genes likely to contribute to plant-microbe interactions, suggesting that there is still much to learn about how soft rot bacteria cause disease.