title: Soybean proteins GmTic110 and GmPsbP are crucial for chloroplast development and function.
abstract: We have identified a viable-yellow and a lethal-yellow chlorophyll-deficient mutant in soybean. Segregation patterns suggested single-gene recessive inheritance for each mutant. The viable- and lethal-yellow plants showed significant reduction of chlorophyll a and b. Photochemical energy conversion efficiency and photochemical reflectance index were reduced in the viable-yellow plants relative to the wildtype, whereas the lethal-yellow plants showed no electron transport activity. The viable-yellow plants displayed reduced thylakoid stacking, while the lethal-yellow plants exhibited failure of proplastid differentiation into normal chloroplasts with grana. Genetic analysis revealed recessive epistatic interaction between the viable- and the lethal-yellow genes. The viable-yellow gene was mapped to a 58kb region on chromosome 2 that contained seven predicted genes. A frame shift mutation, due to a single base deletion in Glyma.02g233700, resulted in an early stop codon. Glyma.02g233700 encodes a translocon in the inner membrane of chloroplast (GmTic110) that plays a critical role in plastid biogenesis. The lethal-yellow gene was mapped to an 83kb region on chromosome 3 that contained 13 predicted genes. Based on the annotated functions, we sequenced three potential candidate genes. A single base insertion in the second exon of Glyma.03G230300 resulted in a truncated protein. Glyma.03G230300 encodes for GmPsbP, an extrinsic protein of Photosystem II that is critical for oxygen evolution during photosynthesis. GmTic110 and GmPsbP displayed highly reduced expression in the viable- and lethal-yellow mutants, respectively. The yellow phenotypes in the viable- and lethal-yellow mutants were due to the loss of function of GmTic110 or GmPsbP resulting in photooxidative stress.
authors.affiliation: USDA-ARS, US Salinity Lab, Riverside, CA 92507, USA. Electronic address: Devinder.sandhu@ars.usda.gov.
authors.forename: Devinder
authors.initials: D
authors.lastname: Sandhu
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA. Electronic address: tayatkinson25@gmail.com.
authors.forename: Taylor
authors.initials: T
authors.lastname: Atkinson
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA. Electronic address: anoll226@gmail.com.
authors.forename: Andrea
authors.initials: A
authors.lastname: Noll
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA. Electronic address: Callie.Johnson@landmark.coop.
authors.forename: Callie
authors.initials: C
authors.lastname: Johnson
authors.affiliation: Department of Agronomy, Iowa State University, Ames, IA 50011-1010, USA. Electronic address: kt.espinosa67@gmail.com.
authors.forename: Katherine
authors.initials: K
authors.lastname: Espinosa
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA. Electronic address: jboelt92@gmail.com.
authors.forename: Jessica
authors.initials: J
authors.lastname: Boelter
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA. Electronic address: sabel728@gmail.com.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Abel
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA; Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, Punjab, India. Electronic address: dhattbalpreet03@gmail.com.
authors.forename: Balpreet K
authors.initials: BK
authors.lastname: Dhatt
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA. Electronic address: tbarta@uwsp.edu.
authors.forename: Terese
authors.initials: T
authors.lastname: Barta
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA; Natural Resources Research Institute, University of Minnesota, Duluth, MN, 55811, USA. Electronic address: esingsaa@d.umn.edu.
authors.forename: Eric
authors.initials: E
authors.lastname: Singsaas
authors.affiliation: Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA. Electronic address: ssepsenw@uwsp.edu.
authors.forename: Sol
authors.initials: S
authors.lastname: Sepsenwol
authors.affiliation: Department of Agronomy, Iowa State University, Ames, IA 50011-1010, USA. Electronic address: susana@iastate.edu.
authors.forename: A Susana
authors.initials: AS
authors.lastname: Goggi
authors.affiliation: Department of Agronomy, Iowa State University, Ames, IA 50011-1010, USA.
authors.forename: Reid G
authors.initials: RG
authors.lastname: Palmer
mesh_terms: D002734:Chlorophyll / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D004252:DNA Mutational Analysis; D004843:Epistasis, Genetic; D005808:Genes, Recessive; D009154:Mutation; D045332:Photosystem II Protein Complex / Q000235:genetics; D013025:Glycine max / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
chemical_list: D045332:Photosystem II Protein Complex; D002734:Chlorophyll
keywords: Chlorophyll-deficient; Photosynthesis; PsbP; Soybean; Tic110