Venue: Room 506 Museum for Aquatic Organisms

Speaker: Ling Li, Adjunct Assistant Professor & Associate Scientist

                 Genetics, Development and Cell Biology, Iowa State University 

Title: An Arabidopsis orphan gene modulates carbon allocation across species 

Introduction: 

The genome of each species contains as high as 8% of genes that are uniquely present in that species. Little is known about the functional significance of these so-called species-specific or orphan genes. Qua Quine Starch (QQS) is a species-specific Arabidopsis thaliana orphan gene. Altering QQS expression in Arabidopsis impacts carbon partitioning into starch and protein. Although only recognizable by sequence in A. thaliana, when QQS is introduced into ectopic species such as soybean, rice and corn, carbon partitioning in leaf and seed of these plants show decreased starch and increased protein. For example, soybean lines expressing QQS have indistinguishable morphology from control lines, but 5-80% decreased leaf starch and 6-60% increased leaf protein; seeds contain 0-13% less oil and protein content is increased by 10-18%. QQS increases seed protein content by 6-11% in five high, medium and low protein soybean cultivars. Using a variety of approaches, including proteomics, and computational analysis of mRNA-seq from QQS-expressing soybean lines, we have identified a major QQS interactor which is central to the molecular mechanism of QQS function. Altering expression of this interactor has the similar effects on carbon allocation as does altering QQS expression. Taken together, these data broaden the concept of QQS as a modulator of carbon allocation, demonstrate that this species-specific gene can affect protein and carbohydrate content of diverse agronomic species, and begin to reveal the skeleton of a previously undefined network in which QQS participates.