Plant Molecular Biology

In nature, plants are living in constantly changing environments that are often unfavorable or stressful for growth and development. Adverse environmental conditions, including drought, extreme temperatures, and salinity, constitute major limiting factors for plant geographical distribution and productivity in agriculture, and threaten food security. These conditions are expected to increase along this century due to drastic changes in climate.

To survive and reproduce under stressful environmental conditions, some plants have evolved sophisticated adaptive responses, most of them controlled through extensive reprogramming of gene expression. Although many stress-regulated genes have already been identified and characterized, the molecular mechanisms underlying those adaptive responses remain largely unknown. Elucidating these mechanisms, in addition of being a fundamental biological issue, is significant from a practical point of view. Our research program is aimed to identify and characterize those mechanisms. Using Arabidopsis as a model system and a multidisciplinary experimental approach, we have unveiled new posttranscriptional regulatory modules involved in plant adaptation to abiotic stresses. In particular, we have shown that core components of the spliceosome, such as the LSM2-8 complex and the SME1 protein, operate by controlling the correct splicing of specific pre-mRNAs, depending on the environmental conditions. The environmental conditions also determine the ability of the LSM1-7 complex, a mRNA decapping activator, to control the adequate life span of selected transcripts. In both cases, the specificity for some pre-mRNAs and mRNAs imposed by the environment leads to particular patterns of gene expression that fine-tune plant responses to abiotic stresses. Current efforts are mainly dedicated to identify the molecular determinants of these specificities, as well as to investigate the role of the Arabidopsis PAT1 proteins, another mRNA decapping activators, in abiotic stress responses. The conservation of the posttranscriptional regulatory modules identified in Arabidopsis in important crops such as tomato is also being a subject of study.