Evolvable Features of Lignin Pathway in Wheat under Water Stress

Abstract

Recent advances in plant genomics have led to the identification of a vast number of potentially beneficial waterstress-
related genes, plus technologies for gene over-expression or silencing. The characterization of key plant
physiological mechanisms that restrain plant performance under drought, together with the associated regulatory
genes, could therefore facilitate the development by breeders of improved crop varieties showing increased wateruse
efficiency and drought resistance. Plant growth is the result of daughter-cell production by meristematic cell
divisions and subsequent massive expansion of the young cells. Cell expansion is in turn dependent on biophysical
changes, which include a regulated loosening of primary cell walls and subsequent yielding to the hydrostatic (turgor)
pressure generated by solute and water uptake into the cells. Lignin is a core component of plant cell wall and it
is important for water transport, structural integrity, rigidity and pest resistance. Our light microscope and
electronmicrographs data on three wheat (hexaploid) cultivars HD 2428 (drought susceptible), HD2285 (thermotolerant)
and C306 (drought tolerant) displayed that weak linkage between lignin gene function and metabolic outcome may
be advantageous, since it may enhance the tolerance, flexibility and robustness of metabolic regulation.