The enhanced expression of PLD genes and the quantitative increase in the level of phosphatidic acid (PA) in resistant Sinapis alba compared to the downregulated or unchanged expression of the PLD genes and decreased PA level in susceptible Brassica juncea when challenged with Alternaria brassicicola, indicated a positive relationship between PA-mediated signalling and resistance against this necrotrophic pathogen. Furthermore, spraying PA onto the susceptible species B. juncea increased resistance and enhanced expression of ABA-responsive genes, which was comparable to the expression of these genes in S. alba when challenged with A. brassicicola.
•The enhanced expression of several PLD genes in resistant S. alba was observed compared to B. juncea upon challenge with A. brassicicola.
•An increase in the PA level in S. alba compared to B. juncea following interaction with the pathogen.
•Leaves of B. juncea incubated on PA-soaked filter paper did not show resistance.
•Spraying B. juncea leaves with PA led to resistance as well as to the enhanced expression of ABA-responsive genes.
•A temporal increase in the PA level is associated with increased resistance against A. brassicicola.
Traditional methods of quantifying the harmful effects of invertebrates on plants require time-consuming identification of large numbers of individuals at species level. Collected specimens usually are killed; this may be unacceptable for some strictly protected species and may bias the results of subsequent surveys at the same site.
We developed a “harmfulness scale” for quick, non-invasive assessment of invertebrate impacts on plants, and used the scale to test differences in invertebrate attack on species of Balsaminaceae, Polygonaceae and Asteraceae growing in lowland and mountains in Poland. In 2010–2011, we recorded 9190 invertebrates and identified them in situ to family or superfamily level. Among them were 7593 pests, accounting for 82.6% of all recorded organisms. Pests were three times more numerous in the mountains than in the lowland. Balsaminaceae were most heavily attacked by pests (92.9% of all organisms detected on them). Aphidoideae were the most numerous pests.
This method can help reduce the costs and labour required for this type of research, facilitating progress in theoretical biology and in the development of practical phytosanitary measures. 相似文献