Senescence, dormancy and tillering in perennial C4 grasses

Authors: Sarath, Gautam; BAIRD, LISA - University Of San Diego; Mitchell, Robert - Rob

Submitted to: Plant Science
Publication Type: Review Article
Publication Acceptance Date: 12/15/2013
Publication Date: 1/14/2014
Publication URL: http://handle.nal.usda.gov/10113/58302
Citation: Sarath, G., Baird, L., Mitchell, R. 2014. Senescence, dormancy and tillering in perennial C4 grasses. Plant Science. 217-218C (2014):140-151.

Interpretive Summary: Warm-season, perennial grasses that can grow on marginal soils of the temperate regions of the world have been tabbed as sources of biomass for the production of biofuels and green chemicals. An important feature of these species is their ability to grow year after year, producing abundant biomass from tiller buds initiated on the below-ground portions of the plant. Although there is increasing knowledge on the agronomy and management of these species as crops, there is limited information on the molecular and cellular machinery that underlie most aspects of plant development. A distinct aspect of these temperate warm-season grasses is their ability to enter into dormancy with the onset of winter, and exit out of dormancy with the onset of spring. In this manuscript the work performed on the molecular aspects of senescence and dormancy in other plants is reviewed as a means to develop models that can be used in the future study of these processes in perennial warm-season grasses such as switchgrass.

Technical Abstract: Perennial, temperate, C4 warm-season grasses, such as switchgrass and miscanthus have been tabbed as sources of herbaceous biomass for the production of green fuels and chemicals based on a number of positive agronomic traits. Although there is important literature on the management of these species for biomass production on marginal lands, numerous aspects of their biology are as yet unexplored at the molecular level. Perenniality, a key agronomic trait, is a function of plant dormancy and winter survival of the below-ground parts of the plants. These include the crowns, rhizomes and meristems that will produce tillers. Maintaining meristem viability is critical for the continued survival of the plants. Plant tillers that emerge from the dormant crown and rhizome meristems at the start of the growing period in the spring, progress through a phase of vegetative growth, followed by flowering and eventually undergo monocarpic senescence. There is nutrient mobilization from the aerial portions of the plant to the crowns and rhizomes during tiller senescence. Signals arising from the shoots and from the environment can be expected to be integrated as the plants enter into dormancy. Plant senescence and dormancy have been well studied in several dicot species and offer a robust framework to develop testable models to understand these processes in temperate C4 perennial grasses. The availability of latitudinally adapted populations for switchgrass presents an opportunity to dissect differential mechanisms that can impact senescence, dormancy and winter survival. Given the large increase in genomic and other resources for switchgrass, it is anticipated that projected studies with switchgrass will have a broader impact on related species.