Abstract Detail

Botanical foundations for perennial agriculture: Evolution and ecology of perennial herbaceous plants

Jaikumar , Nikhil S [1], Dorn, Kevin [2], Snapp, Sieglinde [3].

Acclimation to freezing stress in Thinopyrum intermedium cohorts of varying ages: DNA damage repair and oxidative stress mitigation.

The effect of plant age on abiotic stress tolerance is an under-studied question, although some theoretical arguments suggest that up to a point, plants should increasingly invest in stress tolerance at the cost of growth and reproduction as they age. While some data from woody perennials supports this argument, very few studies have considered interactions of age and abiotic stress in herbaceous perennials. In a series of field studies, we compared intermediate wheatgrass (Thinopyrum intermedium) plants of varying ages under both conditions of winter freezing stress (December - February) and under less stressful conditions in fall and spring. Indices of freezing tolerance included overexpression of DNA damage repair genes, and activity of antioxidative enzymes. Both large age differences (1-2 year old vs. 6-7 year old) and smaller age differences (6-7 year old vs 3 year old) were considered. Key findings were the following:
1) Older plants had greater activity of several antioxidative enzymes, under winter freezing stress, than first-year or second-year plants.
2) Three year old plants showed similar levels of antioxidative enzyme activity and similar retention of photosynthetic capacity as six- or seven-year-old plants.3) Two DNA damage repair genes (CPD photolyase and ERCC1) were overexpressed under winter freezing stress, but were equivalent or at higher levels in the three-year cohort compared to the seventh-year plants.Combining these findings, we see a clear age-related trend in which first- and second-year intermediate wheatgrass appear to prioritize growth and seed yield at the expense of winter stress tolerance. However, by the third year a 'mature' phenotype is reached and no further age-related differences in freezing stress tolerance are seen. This study contributes to a small but growing literature on effects of age on stress tolerance in herbaceous perennials. It also stands out as one of the first investigations to document overexpression of these two DNA repair genes under cold stress in a plant.

1 - University of Illinois, Institute for Genomic Biology, 1206 West Gregory Drive, Room 1500, Urbana, IL, 61820, USA
2 - Kansas State University, Department of Agronomy, 4713 Throckmorton PSC, Manhattan, KS, 66506
3 - Michigan State University, Plant, Soil and Microbial Science, Room 490, 1066 Bogue Street , East Lansing, MI, 48824, USA

Keywords:
Freezing tolerance
age
DNA damage repair.

Presentation Type: Colloquium Presentations
Session: C02, Botanical foundations for perennial agriculture: Evolution and ecology of perennial herbaceous plants
Location: 102/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 9:30 AM
Number: C02006
Abstract ID:555
Candidate for Awards:None