Effect of temperature and resistance of tobacco cultivars to the progression of bacterial wilt, caused by Ralstonia solanacearum

Abstract

Background and aims Resistant cultivars are one of the most effective control measures used against bacterial wilt, caused by the soilborne bacterium Ralstonia solanacearum. We aimed to determine the effect of temperature and resistance of tobacco varieties on bacterial wilt occurrence. Methods Five tobacco cultivars, with varying resistance levels, were inoculated and transferred to growth chambers at 10, 15, 20, 25, 30, and 35°C. The growth rate of R. solanacearum was also studied in culture at 10, 20, and 30°C. The mechanism of resistance was further examined in histological studies conducted at 10, 20, and 30°C with strain AW1-gfp38 that expresses green fluorescent protein.Results The highest disease incidence was observed at 30 and 35°C, while no symptoms were observed at 10 and 15°C. Strains grew in culture at all temperatures. At 30°C the low resistant cultivars had the most stems colonized by the bacterium, while the highly resistant cultivars mainly had localized infections in the roots. Conclusions We suggest that the mechanism of resistance in tobacco is associated with the ability to limit colonization of stem tissues and is temperature dependent. Evaluation of restricted root infections in breeding lines may provide a means for early screening of resistance in breeding programs.

Climatic factors determine the yield and quality of Honghe flue-cured tobacco

“…High-temperature forced ripening also reduces the yield and quality of tobacco leaves 18 . Temperature plays a predominant role in affecting the rate of soil carbon mineralization 19 , and tobacco’s resistance mechanisms are also temperature dependent 20 . In addition, the properties of tobacco leaves, such as biomass, leaf area, sugar, nicotine content, etc., are largely influenced by moisture factors 21 .…”

Screening Cultivated Eggplant and Wild Relatives for Resistance to Bacterial Wilt (Ralstonia solanacearum)

“…Differences in bacterial wilt resistance levels between the first and second trials were evident in accessions of S. anguivi, S. sisymbriifolium (SIS2), and S. torvum. The susceptibility or reduction of resistance in the second trial second could be due to the higher temperatures observed in the second trial, which reached 36 • C. Similar results were found in tomato and tobacco (Nicotiana tabacum), where resistant cultivars become susceptible when exposed to temperatures above 28 • C [26,45]. In addition, soil moisture and soil temperature may have influenced the resistance reaction of the genotypes [46].…”

“…Grafting onto resistant rootstocks could also provide an alternative solution to manage soil-borne pathogens, including bacterial wilt, in Solanaceous crops [24,25]. However, bacterial wilt resistance may vary with location, temperature, and strain differences of the pathogen [26]. Further identification of resistance sources to bacterial wilt for breeding, and introgression of resistance genes into eggplant rootstock/cultivar is the best strategy to improve the chances of durable resistance for managing bacterial wilt [2].…”

Tomato Hybrid and Local Varieties Screened for Resistance to Bacterial Wilt Caused by <i>Ralstonia solanacearum</i> under Screen House and Field Conditions

“…Our results are also in line with those of Singh et al [35] who evaluating the effect of temperature, cultivar and induced root wounding on virulence of R. solanacearum in greenhouse tomato crops, showed no wilt symptoms at 20˚C or lower. In addition, Bittner et al [36], breeding tobacco varieties resistant against R. solanacearum, reported the highest incidences when temperatures were between 30˚C and 35˚C and no symptoms at temperatures less than or equal to 15˚C. Oussou et al [16] also reported a high wilt rate of Solanum macrocarpum artificially inoculated with R. solanacearum during the dry period compared to the wet period.…”