Role of salicylic acid signaling in the biotrophy-necrotrophy transition of Xanthomonas campestris pv. campestris infection in Brassica napus

2021 ◽  
Vol 113 ◽  
pp. 101578
Author(s):  
Md Tabibul Islam ◽  
Md Al Mamun ◽  
Bok-Rye Lee ◽  
Van Hien La ◽  
Woo-Jin Jung ◽  
...  
2020 ◽  
Vol 33 (1) ◽  
pp. 13-20
Author(s):  
Muhammad Awais Ghani ◽  
Muhammad Mehran Abbas ◽  
Basharat Ali ◽  
Khurram Ziaf ◽  
Muhammad Azam ◽  
...  

Tri-genomic Brassica napus L.wasdeveloped by the cross between Brassica napusand Brassica nigra. The crop is animportant source of vegetable seed oil in Pakistan,after cotton. The low oilseed rape yield is attributed to high temperature in the production zones. Interspecific hybridization using these two speciescan be helpful to produce heat resistant hybrids. On the other hand, it has been found that foliar application of different plant growth regulators can be used to reduce the heat stress in Brassica. The objectiveof this studywas to test the response of three different tri-genomic hybrids to high temperature stressat seedling stage. Seedlings were foliar sprayed with 0.13 mM salicylic acid (SA) prior to exposure tohigh temperatureat two true leaf stage. The plants were harvested after 30 days of sowing for growth and biochemical analysis. Plants ofV38 showed the highest values for all morphological traits and biochemical activities among the threehybrids. In general, plants exposed to the temperature stress exhibited a significant decline in growth, chlorophyll content and enzyme activity.Foliar application of SA significantly improved leaf and root biomass under heat stress.Further, antioxidativeenzyme activities significantly increased in response to SA either compared to control or to plants exposed to temperature stress.It is concluded thatapplication of salicylic acid elevated activity of antioxidative enzymes and was helpful in mitigating the detrimental effects of high temperature inoil seed rape.


Author(s):  
Mahdi Khozaei ◽  
Shiva Boroumand Jazi

Oilseed plant, Brassica napus L. seedlings grown in hydroponic condition with different concentrations of Pb were treated with salicylic acid (SA) to investigate the role of exogenous salicylic acid in alleviating lead toxicity on biochemical and physiological activities of the plant. The results showed that application of different concentrations of Pb increased soluble sugars and reduced carbohydrate levels significantly in roots and shoots of the plants. The stress induced by application of Pb triggered significant inhibitory effects on growth and chlorophyll synthesis induced on the production of protein and proline and enhanced the levels of antioxidant activity. Salicylic acid (SA) treated plants showed alleviation increasing total dry mass, leaf area, shoot and root length as well as leaf total chlorophyll content in responses to Pb stress. Results revealed the importance of salicylic acid (SA) activity in enabling plants to reduce the soluble sugars and increase of insoluble sugar in heavy -metal-stressed plants. The content of proline and proteins were also reduced in plants were treated with salicylic acid. Our data provide evidence that salicylic acid treatment decreased the activity of antioxidant enzymes in plants were exposed to different levels of Pb.


Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 292-297 ◽  
Author(s):  
M. Lema ◽  
P. Soengas ◽  
P. Velasco ◽  
M. Francisco ◽  
M. E. Cartea

Black rot, caused by Xanthomonas campestris pv. campestris, is one of the most important diseases affecting Brassica crops worldwide. Nine races have been differentiated in X. campestris pv. campestris, with races 1 and 4 being the most virulent and widespread. The objective of this work was to identify sources of resistance to races 1 and 4 of X. campestris pv. campestris in different Brassica napus crops, mainly in the underexplored pabularia group. Seventy-six accessions belonging to four B. napus groups were screened for resistance to two X. campestris pv. campestris races (1 and 4). The strain of race 1 used in this study was more virulent on the tested materials than the strain of race 4. No race-specific resistance was found to race 1. Most cultivars were susceptible except Russian kale, from the pabularia group, which showed some resistant plants and some other accessions with some partially resistant plants. High levels of race-specific resistance to race 4 were found in the pabularia group, and great variability within accessions was identified. Three improved cultivars (Ragged Jack kale, Friese Gele, and Valle del Oro) and four landraces (Russian kale, MBG-BRS0037, MBG-BRS0041, and MBG-BRS0131) showed plants with some degree of resistance to both races, which may indicate that race-nonspecific resistance is involved. These accessions could be directly used in breeding programs, either as improved cultivars or as donors of race-specific resistance to other Brassica cultivars.


2020 ◽  
Vol 46 (4) ◽  
pp. 327-332
Author(s):  
Nayara Lima Baute Zancan ◽  
Nilvanira Donizete Tebaldi

RESUMO A cultura da canola (Brassica napus L. var. oleifera) foi recentemente introduzida na região do Triângulo Mineiro e Alta Paranaíba, MG. A podridão negra causada pela bactéria Xanthomonas campestris pv. campestris (Xcc) é uma das principais doenças da cultura. A bactéria é disseminada pelas sementes e métodos alternativos de controle devem ser avaliados. Diante disso, o objetivo deste trabalho foi avaliar o uso da terapia fotodinâmica, com os corantes Azul de Metileno (AM) e Azul de Toluidina (AT), sob à irradiação, na inibição do crescimento de Xcc in vitro e no tratamento de sementes de canola naturalmente contaminadas com a bactéria. A suspensão bacteriana de Xcc foi tratada com os corantes AM, AT e associação deles (AM+AT) nas concentrações 25, 50 e 100 µmol L-1, irradiadas ou não, e cultivada em meio de cultura, em seguida foi avaliado o número de unidades formadoras de colônias. Sementes de três genótipos de canola foram tratadas com NaCl 0,45% (Testemunha), AM, AT e AM+AT, nas concentrações 100, 50 e 25 µmol L-1, respectivamente, irradiadas ou não. A porcentagem de germinação das sementes, índice de velocidade de emergência, porcentagem de emergência de plântulas e o controle da bactéria nas sementes foram avaliados. Os corantes AM, AT e AM+AT, nas concentrações 100, 50 e 25 µmol L-1 respectivamente, sob irradiação inibiram o crescimento de Xcc in vitro. A combinação dos corantes AM+AT a 25 µmol L-1 pode ser utilizada no tratamento das sementes de canola. O controle da bactéria Xcc em sementes de canola naturalmente contaminada não foi possível ser determinada com os diferentes corantes.


1997 ◽  
Vol 10 (7) ◽  
pp. 911-916 ◽  
Author(s):  
Socorro Martínez ◽  
Jaime Martínez-Salazar ◽  
Alberto Camas ◽  
Rosalba Sánchez ◽  
Gloria Soberón-Chávez

Xanthomonas campestris pv. campestris NRRL B1459 recA mutants were isolated by recombination with an interrupted Rhizobium etli recA gene and selection of double recombinants. The mutants were impaired in homologous genetic recombination and in DNA repair as judged by their sensitivity to methyl-methane-sulfonate and to UV irradiation; these defects are complemented in trans by the R. etli recA gene. Virulence of X. campestris pv. campestris NRRL B1459 to cabbage is considerably diminished by the recA mutation. The recA mutation is not correlated with the frequency of occurrence of a genetic rearrangement that affects chemotaxis, plant virulence, and xanthan gum production.


Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 491 ◽  
Author(s):  
Xiaorong Zheng ◽  
Birger Koopmann ◽  
Andreas von Tiedemann

Enhanced resistance is a key strategy of controlling ‘Verticillium stem striping’ in Brassica napus caused by the soil-borne vascular pathogen Verticillium longisporum. The present study analyses the role of a broad range of components in the phenylpropanoid and salicylic acid (SA) pathways in basal and cultivar-related resistance of B. napus towards V. longisporum. A remarkable increase of susceptibility to V. longisporum in SA-deficient transgenic NahG plants indicated an essential role of SA in basal resistance of B. napus to V. longisporum. Accordingly, elevated SA levels were also found in a resistant and not in a susceptible cultivar during early asymptomatic stages of infection (7 dpi), which was associated with increased expression of PR1 and PR2. In later symptomatic stages (14 or 21 dpi), SA responses did not differ anymore between cultivars varying in resistance. In parallel, starting at 7 dpi, an overall increase in phenylpropanoid syntheses developed in the resistant cultivar, including the activity of some key enzymes, phenylalanine ammonium lyase (PAL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POX) and the expression of key genes, PAL4, CCoAMT, CCR, POX. As a consequence, a remarkable increase in the levels of phenolic acids (t-cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid) occurred associated with cultivar resistance. A principal component analysis including all 27 traits studied indicated that component 1 related to SA synthesis (PR1, PR2, POX, level of free SA) and component 2 related to lignin synthesis (level of free ferulic acid, free p-coumaric acid, conjugated t-cinnamic acid) were the strongest factors to determine cultivar-related resistance. This study provides evidence that both SA and phenolic acid synthesis are important in cultivar-related resistance, however, with differential roles during asymptomatic and symptomatic stages of infection.


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