News Update on Wilt Disease Research: Jan – 2020

History of Pine Wilt Disease in Japan

Pine wilt induced by the pinewood nematode, Bursaphelenchus xylophilus, may be a great threat to pine forests in Japan. the primary occurrence of the disease was reported in Nagasaki, Kyushu. During the 1930s the disease occurrence was extended in 12 prefectures, and within the 1940s the disease was found in 34 prefectures. The annual loss of pine trees increased from 30,000 m³ to 1.2 million m³ during these 20 years . the big increase in timber loss within the 1970s resulted in 2.4 million m³ of annual loss in 1979. The affected area expanded into 45 prefectures of 47 prefectures in Japan. In cool areas the disease differs in epidemiology from that in heavily infested areas within the warm regions. A national project for controlling pine wilt lays special emphasis on the healthy pine forests predominating throughout cool areas in northern Japan. [1]

Pine Wilt Disease in Korea

In Korea, pine trees are both culturally and spiritually important. consistent with the fourth forest resource survey from 1996 to 2005, pines occur widely on some 1,507,118 ha of land representing 23.5% of Korea’s forest area and 15.1% of the country’s land mass (Kwon 2006). Pines are the dominant tree species in Korean forests even after the attack by the pine caterpillar in 1970s, the outbreak of pine needle gallfly in 1980s, and therefore the occurrence of black pine blast scale in 1980s and 1990s. due to the intense losses from pine wilt , which was first reported in Busan in 1988, this disease may be a serious threat to Korea’s pine forests (Yi et al. 1989). [2]

Phenolic-storing cells: keys to programmed cell death and periderm formation in wilt disease resistance and in general defence responses in plants?

Specialized cells of plants synthesize phenolics and store them in their vacuoles during the traditional processes of differentiation. Such phenolic-storing cells are distributed within most tissues. In some tissues they occur uniformly altogether of the cells, whereas in other tissues they occur randomly scattered, and in still others they seem to be strategically located at potential points of entry. supported the evidence presented herein, it’s proposed that these cells can, first, by decompartmentation, rapid oxidation of their phenolic content, and therefore the ensuing lignification and suberization of cells, and necrobiosis , seal off infections or injuries at the immediate site of cellular penetration and, secondly, if this defence should fail and therefore the stress persist, these same processes promote the prolonged build-up of IAA and ethylene that cause an extra metabolic cascade in outlying cells that has secondary metabolism and growth responses to supply a peridermal defence thorough. [3]

Phage combination therapies for bacterial wilt disease in tomato

Bacteriophages are proposed as an alternate to pesticides to kill bacterial pathogens of crops. However, the efficacy of phage biocontrol is variable and poorly understood in natural rhizosphere microbiomes. We studied biocontrol efficacy of various phage combinations on Ralstonia solanacearum infection in tomato. Increasing the amount of phages in combinations decreased the incidence of disease by up to 80% in greenhouse and field experiments during one crop season. The decreased incidence of disease was explained by a discount in pathogen density and therefore the selection for phage-resistant but slow-growing pathogen strains, along side enrichment for bacterial species that were antagonistic toward R. solanacearum. [4]

Detection of Fusarium solani as a Pathogen Causing Root Rot and Wilt Diseases of Young Olive Trees in Morocco

The cultivation of the fruit tree has several problems associated with pests and diseases which will cause heavy economic losses by causing the death of trees. Fusarium solani was detected within the olive trees of Sidi Taibi’s nurseries located within the national road between Kénitra and Rabat in spring 2012 and 2013 (1 to twenty of diseased plants). Koch’s postulate was verified within the olive trees variety ‘Picholine Moraine’, inoculated withF. solani. Three months after inoculation of the plants, the extremities of the young buds began to dry out, then the drying became generalized and therefore the roots of the inoculated plants showed rot and detached from the bottom of the plants. The pathogen was re-isolated from the roots, dried buds, bark and petioles of the leaves of the inoculated plants; the share of isolation was 100%. [5]

Reference

[1] Mamiya, Y., 1988. History of pine wilt disease in Japan. Journal of nematology, 20(2), (Web Link)

[2] Shin, S.C., 2008. Pine wilt disease in Korea. In Pine wilt disease (pp. 26-32). Springer, Tokyo. (Web Link)

[3] Beckman, C.H., 2000. Phenolic-storing cells: keys to programmed cell death and periderm formation in wilt disease resistance and in general defence responses in plants?. Physiological and Molecular Plant Pathology, 57(3), (Web Link)

[4] Phage combination therapies for bacterial wilt disease in tomato
Xiaofang Wang, Zhong Wei, Keming Yang, Jianing Wang, Alexandre Jousset, Yangchun Xu, Qirong Shen & Ville-Petri Friman
Nature Biotechnology volume 37, (Web Link)

[5] Chliyeh, M., Msairi, S., Touhami, A., Benkirane, R. and Douira, A. (2018) “Detection of Fusarium solani as a Pathogen Causing Root Rot and Wilt Diseases of Young Olive Trees in Morocco”, Annual Research & Review in Biology, 13(5), (Web Link)