Review Article Hailu et al., J Plant Pathol Microbiol 2017, 8:9 DOI: 10.4172/2157-7471.1000419 Journal of Plant Pathology & Microbiology J o u r n a l o f P l a n t P a t h ol o g y & M i c r o b i o l o g y ISSN: 2157-7471 Research Article Open Access Volume 8 • Issue 9 • 1000419 J Plant Pathol Microbiol, an open access journal ISSN: 2157-7471 Keywords: Common blight; Disease rating; Moisture; Phaseolus vulgaris Introduction Common bean (Phaseolus vulgaris L.) is the most widely produced and consumed legume worldwide [1] and occupies an important place in human nutrition. It belongs to the genus Phaseolus, with pinnately compound trifoliate large leaves [2]. Te dietary fbre part of the carbohydrate reduces cholesterol and prevents colon cancer [3], while 18% to 30% dry weight of common beans is protein [4]. It also contains vitamin B and minerals (namely calcium, copper, magnesium, and zinc) and sometimes referred to as a near perfect food [4-6]. Common bean production is limited due to diferent biotic and abiotic factors. Among the abiotic constraints are inadequate total rainfall, erratic rainfall distribution, periodic water stress, extended dry spells during the crop critical growth as a result of climate change [2,7,8]. Low soil fertility, shortage or excess of mineral salts and extreme lower pH of soil are also the abiotic factors that limit common bean production [9-11]. Te major disease of common bean in east Africa, especially in Ethiopia, that is targeted for the management is common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoloi (Smith) and Xanthomonas axonopodis pv. phaseoloi var. fuscans (Burkholder) [12-16]. Depending on susceptibility of common bean varieties and environmental conditions, CBB may cause yield losses ranging between 10% and 40%, [17-20]. Because common bacterial blight is a warm weather and higher humidity disease, it can cause the greatest damage at warm temperature of 28°C to 32°C [21-23]. Te bacteria survive at the temperature ranges of 25°C to 35°C in the feld on infected seed and plant debris [24-27]. Te global surface temperature is projected to increase from 1.8°C lower scenario to 4°C maximum scenario in 2050s [28]. In arid and semi- arid agro-ecologies, the temperature is expected to be increased with the maximum scenario. When temperature is increasing at an alarming rate, water loss occurs through evapo-transpiration and results in reduction of soil moisture content with increase in relative humidity. Increasing temperature until the optimum level for bacterial strains, and increasing relative humidity creates suitable condition for the development of CBB epidemics in susceptible common bean varieties [26]. However, at higher temperature, above the optimum level for bacterial blight development, especially above 30°C, the heat tolerant, disease resistant and drought resistant varieties adapt to high temperature and lower soil water content [29-31]. Te drought resistant and disease resistant common bean varieties develop several adaptation mechanisms that allow the plant survival during hot and dry conditions [7,32]. Te high temperature causes water defcit due to excessive transpiration that could adversely afect the development and function Effects of Temperature and Moisture on Growth of Common Bean and Its Resistance Reaction against Common Bacterial Blight (Xanthomonas axonopodis pv. phaseoli strains) Hailu N 1 *, Fininsa C 2 , Tana T 2 and Mamo G 3 1 Department of Plant Sciences, Debreberhgan University, Debereberhan, Ethiopia 2 School of Plant Sciences, Haramaya University, Dire Dawa, Ethiopia 3 Ethiopian Institute of Agricultural Research (EIAR), Addis Ababa, Ethiopia Abstract Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli Smith (Xap) and Xanthomonas axonopodis pv. phaseoli var. fuscan Burkholder (Xapf) is the most serious biotic constraint of common bean (Phaseolus vulgaris L.) production. Variables temperature and moisture are dominant climate factors that affect common bean growth as well as the development of CBB epidemics. Two sets of experiments were conducted in the Plant Pathology Laboratory of Haramaya University) to assess the effect of temperature and moisture on the resistance level of common bean in 2014 and 2015. In the frst experiment, two common bean varieties (Gofta and Mexican 142) were inoculated with two bacterial strains (Xap and Xapf) and a control were incubated at four temperature levels (28°C, 30°C, 32°C and 34°C) in growth chambers. In the second experiment, three-soil moisture levels (100%, 75% and 50%) were employed to that of experiment one. The treatment combinations were arranged in factorial completely randomized design (CRD) in the growth chambers for both series of experiments. The disease rating was signifcantly (P<0.05) affected by common bean varieties and temperature levels at 17 days after inoculation (DAI). Higher disease rating was recorded on the variety Mexican 142 than on Gofta. The highest (1.75) mean disease rating was recorded at 28°C and the lowest (1.44) at 34°C. The mean disease ratings differed signifcantly among the moisture levels. The highest (2.01) mean disease rating was recorded from 75% moisture content, while the lowest (1.80) disease rating was obtained from 50% moisture content. The results of these series of experiments indicated that climate change effects above optimum level would not be favorable for CBB development in the arid and semi-arid agro ecologies unless new bacterial strains adapted to the drought tolerant common beans in the area. *Corresponding author: Hailu N, Department of Plant Sciences, Debreberhgan University, P.O. Box 445, Debereberhan, Ethiopia, Tel: 82-31-670-5420; E-mail: negash.hailu17@gmail.com Received September 05, 2017; Accepted September 22, 2017; Published September 26, 2017 Citation: Hailu N, Fininsa C, Tana T, Mamo G (2017) Effects of Temperature and Moisture on Growth of Common Bean and Its Resistance Reaction against Common Bacterial Blight (Xanthomonas axonopodis pv. phaseoli strains). J Plant Pathol Microbiol 8: 419. doi: 10.4172/2157-7471.1000419 Copyright: © 2017 Hailu N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.