Nevada Dividends!

Increasing Seed Set Yields in Stressed Plants


Issue:

Each year crop yields are severely impacted by a variety of stress conditions, including heat, cold, drought, hypoxia, and salt.  Reproductive development in flowering plants is highly sensitive to hot or cold temperatures, with even a single hot day or cold night sometimes being fatal to reproductive success. In many plants, pollen tube development and fertilization is the “weakest link”.  The focus of this research is on developing two strategies to improve stress tolerance in pollen production.

What has been done?

In the past year, NAES scientists tested whether stress tolerance can be improved by expressing two different transcription factors that regulate stress responses in vegetative tissues, but are not expressed in pollen. Cyclic nucleotide-gated channels (CNGC16) plants were made (transgenics) and tested for changes in pollen stress tolerance. Finally, profiling sets of RNA molecules to identify temperature-dependent changes in gene expression that occur in pollen. The team performed RNA-sequencing analyses for pollen grains harvested from wild type Arabidopsis plants (and CNGC16 mutants), and two tomato cultivars (one being heat tolerant) under control and heat stress conditions.

Results:

NAES scientists in collaboration with an Italian lab, produced work that provides biochemical evidence to establish the auto-inhibited Ca2+-ATPases (ACA12) as the first example of an ACA-type calcium pump that appears to be constitutively active. 

The discovery that knocking out an enzyme involved in cell wall functioning (TBL14) has provided the first genetic evidence that links a specific calcium signaling pathway with the function of a specific protein involved in plant cell wall biogenesis. 

NAES scientists obtained genetic evidence that the complete loss plasma membrane calcium pumps is not lethal to the model plant Arabidopsis, but does result in a phenotype in which the plant fails to bolt and produce reproductive structures.

Finally, the team uncovered genetic evidence that increased stress tolerance can be obtained by expression of a galactinol synthase gene.  This research has provided preliminary evidence that will allow scientists to manipulate the complete set of small-molecule chemicals found within pollen to improve reproductive fitness under stress conditions.

CONTACT INFORMATION

Jeff Harper

Department of Biochemistry and Molecular Biology

1664 North Virginia Street

Reno, Nevada   89557

 

Phone: (775) 784-1349

Email: jfharper@unr.edu

Personal Web Site: