| Sugarcane genes Associated with Sucrose Content
Papini-Terzi, Flávia Riso
Rocha, Ricardo Zorzetto Nicoliello Vêncio, Juliana Felix,
Diana Branco, Alessandro Jaquiel Waclawovski, Luiz Eduardo Vieira Del Bem, Carolina Gimiliani
Lembke, Maximiller Dal-Bianco Lamas Costa, Milton Yutaka
Nishiyama-Jr, Renato Vicentini, Michel Vincentz, Eugênio
César Ulian, Marcelo Menossi, Gláucia Mendes Souza*
- Sucrose content
is a highly desirable trait in sugarcane as the worldwide demand for cost-effective
biofuels surges. Sugarcane cultivars differ in their capacity to accumulate sucrose
and breeding programs routinely perform crosses to identify genotypes able to produce
more sucrose. Sucrose content in the mature internodes reach around 20% of the culms
dry weight. Genotypes in the progenies reflect their genetic program and may display
contrasting growth, development, and physiology, all of which affect carbohydrate
metabolism. Few studies have profiled gene expression related to sugarcane?s sugar
content. The identification of signal transduction components and transcription factors
that might regulate sugar accumulation is highly desirable if we are to improve this
characteristic of sugarcane plants.
- We have compared thirty
genotypes that have different Brix (sugar) levels and identified genes differentially
expressed in internodes using cDNA microarrays. These genes were compared to existing gene
expression data for sugarcane plants subjected to diverse stress and hormone treatments.
The comparisons revealed a strong overlap between the drought and sucrose-content datasets
and a limited overlap with ABA signaling. Genes associated with sucrose content were extensively
validated by qRT-PCR, which highlighted several protein kinases and transcription factors that
are likely to be regulators of sucrose accumulation. The data also indicate that aquaporins,
as well as lignin biosynthesis and cell wall metabolism genes, are strongly related to sucrose
accumulation. Moreover, sucrose-associated genes were shown to be directly responsive to short
term sucrose stimuli, confirming their role in sugar-related pathways.
expression analysis of sugarcane progenies contrasting for sucrose content indicated a possible
overlap with drought and cell wall metabolism processes and suggested signaling and transcriptional
regulators to be used as molecular markers in breeding programs or as primary targets in a sugarcane
improvement program based on transgenic plants.