Comprehensive analysis of SWEET family genes in Eucalyptus (Eucalyptus grandis)

Abstract

SWEET family genes play an important role in different physiological processes, including sugar transport and adjustments, plant development and environmental adaptability. BLAST tools and Hidden Markov Model-directed sequence alignments in Eucalyptus grandis genome identified 52 Eucalyptus SWEET genes containing MtN3/saliva domain. Out of these, 40 genes encode predicted proteins that have 6 or more transmembrane regions with two MtN3/saliva domains. Six predicted proteins contained only one MtN3/saliva domain, similar to the structure of microbial SemiSWEETs. Of the 52 SWEET candidates, only 45 SWEET family genes were mapped on 8 chromosomes, and most of them showed clustered distribution. The expression profiles revealed that the SWEET genes have different expression in different tissues, showing that they might play different functions in Eucalyptus. Our results explored the evolutionary aspects, provided a systematic description of Eucalyptus SWEET genes and can help researchers to understand the functions of the SWEET family genes in Eucalyptus.