Systemic fungicidal activity of phenazine‐1‐carboxylic acid‐valine conjugate against tobacco sore shin and its translocation and accumulation in tobacco (Nicotiana tabacum L.)

• Published in: Pest management science Vol. 78; no. 3; pp. 1117 - 1127
• Main Authors: Zhu, Xiang, Zhang, Min, Xiao, Yongxin, Hsiang, Tom, Hu, Ciyin, Li, Junkai
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-03-2022; Wiley Subscription Services, Inc
• Subjects: Amino acids; Antifungal activity; Carboxylic acids; Conjugates; Foliage; Fungal diseases; Fungicidal activity; Fungicides; In vivo methods and tests; Mobility; Nicotiana; Nicotiana tabacum; Phenazine; Phenazines; phenazine‐1‐carboxylic acid (PCA); Phloem; Seedlings; soil‐borne diseases; systemicity; Tobacco; tobacco seedlings; Translocation; Valine; Vascular system (plant anatomy); systemicity; phenazine-1-carboxylic acid (PCA); soil-borne diseases; tobacco seedlings; fungicidal activity
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.6724

BACKGROUND
Tobacco sore shin caused by Rhizoctonia solani Kühn is a major soil‐borne fungal disease of tobacco, gradually causing infected stems to become thin and dry, leading to great losses to Chinaʼs tobacco industry. Fungicides with phloem mobility are needed for application to foliage to effectively control root or vascular system pathogens. In this study, phenazine‐1‐carboxylic acid‐valine conjugate (PCA‐Val) with strong phloem mobility was tested for control of tobacco sore shin. In vitro fungicidal activity, systemicity, and in vivo efficacy of PCA‐Val against R. solani in tobacco seedling were evaluated.
RESULTS
In vitro fungicidal activity of PCA‐L‐Val against R. solani was lower than that of PCA or PCA‐D‐Val, but the in vivo protective activity and curative activity of PCA‐L‐Val was the highest among these chemicals tested. The systemicity tests in tobacco seedlings revealed that PCA did not possess phloem mobility, while PCA‐L‐Val and PCA‐D‐Val exhibited strong phloem mobility and could be transported and accumulated in the lower part of the seedling as well as throughout the phloem. In addition, we also found that, just like reported hormone amino acid conjugates, PCA‐L‐Val could be hydrolyzed by tobacco seedlings, to release free PCA.
CONCLUSIONS
The current research results indicated that PCA‐L‐Val possess good phloem transport in tobacco and promising in vivo antifungal activity against R. solani, which can be used as a phloem‐mobile fungicide against tobacco sore shin in production practice.
The current research results indicated that phenazine‐1‐carboxylic acid‐l‐valine conjugate (PCA‐L‐Val) could be developed as a phloem‐mobile fungicide against tobacco sore shin, and provide a better understanding of phloem‐mobile fungicides against soil‐borne or vascular diseases.
© 2021 Society of Chemical Industry.