Alternative Splicing of a Host Defense Regulatory Gene in Soybean (Glycine max) 
P. SELIG (1), V. Nalam (1) (1) Indiana University-Purdue University, U.S.A.

Alternative splicing (AS) plays an important role in post-transcriptional regulation in higher eukaryotes. Technological advances in high-throughput sequencing over the past decade have revealed the extent of AS in several plant species. In soybeans, up to 63% of genes undergo AS in response to a variety of stimuli and biotic stressors. With respect to plants defense, AS events have been observed in resistance (R) genes. However, there have been no reports of AS occurring in defense regulatory genes. PHYTOALEXIN DEFICEINT4 (PAD4) is an important regulator of host defenses and in soybean elevated PAD4 expression is associated with increased resistance to soybean aphids and to nematodes.  Interestingly, our research shows that an alternatively spliced variant of PAD4 also occurs in soybean plants.  Our data shows that the proportion of the PAD4 splice variant, PAD4-AS1, changes in response to soybean aphid infestation. Therefore, the overall objective of the work is to determine the role of PAD4-AS1 in plant defense. The specific objectives of this study are to; (1) to determine the role of soybean PAD4 and PAD4-AS1 in Arabidopsis and 2) determine the sub-cellular localization of PAD4 and PAD4-AS1. Towards this end, PAD4 and PAD4-AS1 RNA will be extracted from soybean leaf tissue, transcribed into cDNA and amplified using polymerase chain-reaction. The amplified products will be introduced into a plant expression vector. Once cloned the recombinant plant expression plasmids will be introduced into soybean protoplasts in order to determine sub-cellular localization using confocal microscopy. Findings from this research will provide a better understanding to this important signaling system and better understanding of PAD4’s role in host defense.

Abstract Number: P16-470
Session Type: Poster