eIFiso4G Augments the Synthesis of Specific Plant Proteins Involved in Normal Chloroplast Function

Authors

Andrew D. Lellis, University of Texas at Austin
Ryan M. Patrick, University of Texas at Austin
Laura K. Mayberry, University of Texas at Austin
Argelia Lorence, Arkansas State University – JonesboroFollow
Zachary C. Campbell, Arkansas Biosciences Institute at A-State
Johnna L. Roose, Louisiana State University
Laurie K. Frankel, Louisiana State University
Terry M. Bricker, Louisiana State University
Hanjo A. Hellmann, Washington State University
Roderick W. Mayberry, University of Texas at Austin
Ana Solis Zavala, University of Texas at Austin
Grace S. Choy, University of Texas at Austin
Dennis C. Wylie, University of Texas at Austin
Mustafa Abdul-Moheeth, University of Texas at Austin
Adeeb Masood, University of Texas at Austin
Amy G. Prater, University of Texas at Austin
Hailey E. Van Hoorn, University of Texas at Austin
Nicola A. Cole, University of Texas at Austin
Karen S. Browning, University of Texas at Austin

Document Type

Article

Publication Title

Plant Physiology

MeSH Headings (Medical Subject Headings)

Agriculture; Plant Sciences

Abstract

The plant-specific translation initiation complex eIFiso4F is encoded by three genes in Arabidopsis (Arabidopsis thaliana)—genes encoding the cap binding protein eIFiso4E (eifiso4e) and two isoforms of the large subunit scaffolding protein eIFiso4G (i4g1 and i4g2). To quantitate phenotypic changes, a phenomics platform was used to grow wild-type and mutant plants (i4g1, i4g2, i4e, i4g1 x i4g2, and i4g1 x i4g2 x i4e [i4f]) under various light conditions. Mutants lacking both eIFiso4G isoforms showed the most obvious phenotypic differences from the wild type. Two-dimensional differential gel electrophoresis and mass spectrometry were used to identify changes in protein levels in plants lacking eIFiso4G. Four of the proteins identified as measurably decreased and validated by immunoblot analysis were two light harvesting complex binding proteins 1 and 3, Rubisco activase, and carbonic anhydrase. The observed decreased levels for these proteins were not the direct result of decreased transcription or protein instability. Chlorophyll fluorescence induction experiments indicated altered quinone reduction kinetics for the double and triple mutant plants with significant differences observed for absorbance, trapping, and electron transport. Transmission electron microscopy analysis of the chloroplasts in mutant plants showed impaired grana stacking and increased accumulation of starch granules consistent with some chloroplast proteins being decreased. Rescue of the i4g1 x i4g2 plant growth phenotype and increased expression of the validated proteins to wild-type levels was obtained by overexpression of eIFiso4G1. These data suggest a direct and specialized role for eIFiso4G in the synthesis of a subset of plant proteins.

First Page

85

Last Page

96

DOI

10.1104/pp.19.00557

Publication Date

9-1-2019

Comments

This article is also available as open access on the publisher's website.

Recommended Citation

Lellis, Andrew D.; Patrick, Ryan M.; Mayberry, Laura K.; Lorence, Argelia; Campbell, Zachary C.; Roose, Johnna L.; Frankel, Laurie K.; Bricker, Terry M.; Hellmann, Hanjo A.; Mayberry, Roderick W.; Zavala, Ana Solis; Choy, Grace S.; Wylie, Dennis C.; Abdul-Moheeth, Mustafa; Masood, Adeeb; Prater, Amy G.; Van Hoorn, Hailey E.; Cole, Nicola A.; and Browning, Karen S., "eIFiso4G Augments the Synthesis of Specific Plant Proteins Involved in Normal Chloroplast Function" (2019). Arkansas Biosciences Institute. 114.
https://arch.astate.edu/abi/114