Project description:To investigate the impact of a plant´s response to abiotic stress on plant defense against subsequent biotic stress, we determined the transcriptional response of Arabidopsis thaliana to low temperature stress (4°C) and subsequent mechanical wounding or larval feeding damage by the herbivores Mamestra brassicae (generalist) and Pieris brassicae (specialist). In total, 21%, 4% and 14% of all genes responsive to M. brassicae, P. brassicae or mechanical wounding were differentially regulated in previously cold-treated compared to untreated plants.
Project description:Activation of plant defence in Brassica napus L. cv. Westar and transgenic MINELESS plants after attack by Mamestra brassicae (cabbage moth)
Project description:Clubroot disease, caused by Plasmodiophora brassicae Woronin, leads to substantial yield losses in Brassica crops worldwide, including Chinese cabbage. Nevertheless, the molecular mechanisms underlying host defense responses remain poorly understood. In this study, we assessed clubroot resistance by comparing the resistant line ‘CR Jingqiu Xinsanhao’ (JQX3) with the susceptible cultivar ‘Zhongbai 76’ (ZB76) through histological analysis of root tissues and monitoring of disease progression in pot trials. Integrated transcriptomic and metabolomic approaches were employed to characterize the defense mechanisms of JQX3 against P. brassicae infection. Marked metabolic reprogramming was detected during both the primary (3 days after inoculation, DAI) and secondary (10 DAI) infection stages. Four pathways—tyrosine metabolism, phenylpropanoid biosynthesis, valine, leucine and isoleucine biosynthesis, and glucosinolate biosynthesis—were significantly enriched at both time points. Notably, differential expression of key enzymatic genes and accumulation of intermediates in the lignin biosynthesis pathway underscored the importance of lignification in the JQX3–P. brassicae interaction. Furthermore, the intermediates p-coumaric acid and coniferaldehyde markedly inhibited P. brassicae spore germination, demonstrating their direct antifungal activity and potential as natural agents for disease control. These findings elucidate key defense-related pathways in Chinese cabbage and offer valuable insights for the development of sustainable clubroot management strategies.
Project description:Plants within the Brassicaceae family have a unique defence mechanism known as the “glucosinolate-myrosinase” system. Upon tissue disruption by insect herbivores, glucosinolates are hydrolysed by the enzyme myrosinase (EC 3.2.1.147) into a variety of degradation products, which can deter insect herbivory. This process has been termed as “The Mustard Oil Bomb”. Seeds of Brassica napus have been genetically modified to remove myrosinase containing myrosin cells. The modified plants have been named MINELESS due to a lack of toxic mines in seeds. This study aimed to get insights into defence responses of B. napus wild-type and MINELESS seedlings, after being challenged by larvae of the generalist herbivore Mamestra brassicae. The microarray analysis showed 494 and 159 genes to be differentially regulated after M. brassicae feeding on wild-type and MINELESS seedlings, respectively. Many of the observed transcriptional responses i B. napus and the MINELESS mutant are related to those found in Arabidopsis thaliana plants when they are exposed to insects.
