Comparative expression of cell wall related genes in four maize RILs and one parental line of variable lignin content and cell wall degradability

A comparison of gene expression in maize between the parental line F271 and four RILs derived from the cross F288 x F271 was investigated based on hybridization on the 17,555 probes Affymetrix micro-array, targeting nearly one third of the genes present in maize genomes. The parental line had unfavorable alleles for cell wall degradability traits at the major QTL position in bin 6.06, while the set of RILs had both the favorable allele and high cell wall degradability. 360 genes were differentially expressed in the four RIL in comparison to F271, including nine genes underlying the major QTL position and 36 underlying two other OTL positions. However, their proposed function (whenever is described) do not allow us to firmly consider their involvement in the observed variation of cell wall related traits. Only a few genes involved in monolignol biosynthesis or polymerization located elsewhere in the genome were differentially expressed between the four RILs and F271, corroborating with the fact that these genes are probably not involved in major determinants of cell wall degradability in the studied set of lines. Among the investigated regulation factors, three ZmMYB, one NAC and one C3HC4 zinc finger were differentially expressed between the four RILs and F271, but they were not located in bin 6.06. Notwithstanding, the obtained results especially strengthened the probable involvement of these genes in maize secondary wall assembly and/or lignification.