In silico characterization and gene expression analysis of late-embryogenesis abundant proteins of agave tequilana weber var. Azul

Abstract

Background/ Studied species: Agave tequilana Weber var. azul is an important crop in Mexico, used for tequila production. Many species of Agave grow in arid lands and are highly tolerant to those environmental conditions. However, the molecular bases of mechanisms selected in agaves to face abiotic stress, have not been described. Hypotheses: Late-embryogenesis abundant proteins (LEAPs), a superfamily closely associated to abiotic stress responses in plants, are a key element in agave responses to arid environments. Methods: Transcriptomic data from A. tequilana were used to perform in silico analyses to identify genes encoding Agave LEAPs. We compare their structural characteristics and their similarity/divergence with described LEAPs from other plant species using bioinformatics. The abundance of the AteqLEAP transcripts in vegetative organs and in response to high temperatures was determined by qRT-PCR. Results: We identified three structurally different AteqLEAPs. AteqLEA_5Bs show low similarity to LEAPs known as “atypical” (containing LEA_3 domain); and they exhibit an unexpected high and constitutive expression pattern in leaves. But AteqLEA_5C (LEA_2) transcripts are low-expressed in all the organs analyzed. Two isoforms of AteqDHN type SK3 show the typical structural disorder and hydrophilicity of dehydrins and are highly expressed in undeveloped leaves, vegetative meristem and stem. Conclusions: AteqLEAP_5Bs seem to play a major and preventive protective role in fully photosynthetic leaves as in a “primed state”; whereas AteqDHNs presumably play a role protecting tissues in differentiation stage as meristem and developing leaves, and storage tissues such as the agave stem.