The multiple roles of trichomes in two Croton species.

Trichomes are common in plants from dry environments, and despite their recognized role in protection and defense, little is known about their role as absorptive structures and in other aspects of leaf ecophysiology. We combine anatomical and ecophysiological data to evaluate how trichomes affect leaf gas exchange and water balance during drought. We studied two congeneric species with pubescent leaves which co-occur in Brazilian Caatinga: Croton blanchetianus (dense trichomes) and Croton adenocalyx (sparse trichomes). We found a novel foliar water uptake (FWU) pathway in C. blanchetianus composed of stellate trichomes and underlying epidermal cells and sclereids that interconnect the trichomes from both leaf surfaces. The water absorbed by these trichomes is redistributed laterally by pectin protuberances on mesophyll cell walls. This mechanism enables C. blanchetianus leaves to absorb water more efficiently than C. adenocalyx. Consequently, the exposure of C. blanchetianus to dew during drought improved its leaf gas exchange and water status more than C. adenocalyx. C. blanchetianus trichomes also increase their leaf capacity to reflect light and maintain lower temperatures during drought. Our results emphasize the multiple roles that trichomes might have on plant functioning and the importance of FWU for the ecophysiology of Caatinga plants during drought.

Functional annotation and comparative modeling of ligninolytic enzymes from Trametes villosa (SW.) Kreisel for biotechnological applications.

Functional annotation of Trametes villosa genome was performed to search Class II peroxidase proteins in this white-rot fungus, which can be valuable for several biotechnological processes. After sequence identification and manual curation, five proteins were selected to build 3 D models by comparative modeling. Analysis of sequential and structural sequences from selected targets revealed the presence of two putative Lignin Peroxidase and three putative Manganese Peroxidase on this fungal genome. All 3 D models had a similar folding pattern from selected 3 D structure templates. After minimization and validation steps, the best 3 D models were subjected to docking studies and molecular dynamics to identify structural requirements and the interactions required for molecular recognition. Two reliable 3 D models of Class II peroxidases, with typical catalytic site and architecture, and its protein sequences are indicated to recombinant production in biotechnological applications, such as bioenergy.Communicated by Ramaswamy H. Sarma.