Biosynthesis of secondary metabolites in sugarcane

Abstract

A set of genes related to secondary metabolism was extracted from the sugarcane expressed sequence tag (SUCEST) database and was used to investigate both the gene expression pattern of key enzymes regulating the main biosynthetic secondary metabolism pathways and the major classes of metabolites involved in the response of sugarcane to environmental and developmental cues. The SUCEST database was constructed with tissues in different physiological conditions which had been collected under varied situation of environmental stress. This database allows researchers to identify and characterize the expressed genes of a wide range of putative enzymes able to catalyze steps in the phenylpropanoid, isoprenoid and other pathways of the special metabolic mechanisms involved in the response of sugarcane to environmental changes. Our results show that sugarcane cDNAs encoded putative ultra-violet induced sesquiterpene cyclases (SC); chalcone synthase (CHS), the first enzyme in the pathway branch for flavonoid biosynthesis; isoflavone synthase (IFS), involved in plant defense and root nodulation; isoflavone reductase (IFR), a key enzyme in phenylpropanoid phytoalexin biosynthesis; and caffeic acid-O-methyltransferase, a key enzyme in the biosynthesis of lignin cell wall precursors. High levels of CHS transcripts from plantlets infected with Herbaspirillum rubri or Gluconacetobacter diazotroficans suggests that agents of biotic stress can elicit flavonoid biosynthesis in sugarcane. From this data we have predicted the profile of isoprenoid and phenylpropanoid metabolism in sugarcane and pointed the branches of secondary metabolism activated during tissue-specific stages of development and the adaptive response of sugarcane to agents of biotic and abiotic stress, although our assignment of enzyme function should be confirmed by careful biochemical and genetic supporting evidence.

Physiological implications of metabolite biosynthesis for net assimilation and heat-stress tolerance of sugarcane ( Saccharum officinarum) sprouts

“…2). An observed increase in anthocyanins is attributable to increased activity of two key enzymes, phenyl ammonia lyase (PAL) and chalcone synthease (CHS), leading to flavonoids and anthocyanin synthesis under high temperature (Oren-Shamir and Nissim-Levi 1999;França et al 2001;Sachray et al 2002). Although accumulation of anthocyanins was determined for the whole shoot, the most probable location of their synthesis is the epidermis, where they presumably shielded the underlying mesophyll tissues from heat-stress effects.…”

Changes in the composition of phenolic compounds and antioxidant properties of grapevine roots and leaves (Vitis vinifera L.) under continuous of long-term drought stress

“…Phenolic compounds were considered as by-products of metabolic alteration (Solecka 1997). The results investigations unequivocally suggest that phenols not only play a major role in defensive reactions of plants but also influence humans and animals that consume products enriched with phenolic compounds (Franca et al 2001;Amarowicz and Weidner 2009). …”

Influence of abiotic stress during soybean germination followed by recovery on the phenolic compounds of radicles and their antioxidant capacity

“…Recent studies, have demonstrated that secondary metabolites, particularly phenolic compounds, perform important signaling and protective functions in plants. Environmental stresses often lead to intensive biosynthesis of phenolic compounds in plants and, as a consequence, they affect humans' and animals wellbeing [1][2][3]. It is noteworthy that the enhancement of plants' tolerance to adverse effects of environmental conditions would result in much higher yields obtained from the currently cultivated fields.…”