LRR1 and JAO2: two linked Arabidopsis genes involved in plan defence against spider mite = LRR1 y JAO2: dos genes interrelacionados de Arabidopsis implicados en la defensa frente a la araña roja

The two-spotted spider mite Tetranychus urticae is a phytophagous arthropod with an impressive range of host plants and remarkable resistance. Nowadays, it is one of the most damaging agricultural pests and this problem is only predicted to get worse with warmer temperatures and increasing drought as consequences of climate change. Previous studies in this area have proven that jasmonic acid (JA) is a key player in the establishment of a defensive response against spider mite. Characterization of two genes JAO2 and LRR1 present in Arabidopsis thaliana was undergone in this work in order to elucidate their role during defence against spider mite. Both genes were induced upon spider mite infestation, suggesting a potential role in plant defence. Five validated T-DNA insertion lines as mutants and overexpressing lines were selected for further analysis after showing differential gene expression levels compared to wild type Arabidopsis (Columbia accession). Damaged leaf area after mite infestation was quantified by three different methods and a higher resistance for JAO2 mutant lines and a LRR1 knock-down lines was shown. T-DNA insertion lines were also used to evaluate mite performance when feeding on transgenic and non-transgenic lines, corroborating the JAO2 and LRR1 role in plant defence against the spider mite T. urticae. Furthermore, a possible compensatory effect between the 4 JAO2 paralogues was studied and differential gene expression for hormone-related genes upstream JA was observed. Although the entire mechanism by which these two genes offer higher plant fitness against T. urticae is not fully understood, this work sheds some light and offers new insights in plant defence response upon spider mite attack