Periodic Reporting for period 1 - T-REX (Developing healthy crops for EU: T3SS-Recognition EXploration (T-REX) for plant immunity against bacteria)
Período documentado: 2019-01-14 hasta 2021-01-13
The objectives of the project were 1) to identify which of the approx. 25 T3SS proteins is recognized by wheat, 2) to identify which wheat protein functions as receptor to detect this T3SS protein, and 3) to evaluate whether the recognition activates immunity that protects the plant.
Understanding the molecular details of this recognition can potentially be exploited to control serious bacterial diseases in plants and animals. Such strategies include use of selected naturally occurring gene variants, molecularly modified genes or drugs inspired by the structures of the interacting molecules.
In order to identify the wheat protein that functions as receptor for the T3SS, I studied the seven genes, genetically defined to encode candidate receptors. Among those, I concluded a plasma membrane receptor kinase (PMK) and three wall-associated kinases (WAK) to be the obvious candidates. In collaboration with the Chinese Academy of Science, Beijing, knock-out mutants were made in the PMK gene, while this turned out not to be possible in the WAK genes. Studies of the pmk mutant have been delayed by the Covid-19.
I have provided evidence that the wheat responses activated by the T3SS are classical immune responses, and therefore likely to protect the plant against bacterial attack. To test whether this is the case, I inoculated the wheat plants with a Xanthomonas pathogen, but observed no effect on disease development in cultivars able to recognize T3SS. The reason for this result could be a molecular difference between the T3SSs from Xanthomonads and Pseudomonads. I have in the meantime obtained a wheat Pseudomonas pathogen, which I will test in the coming months.