ISOLATION OF A CDNA CLONE (ACCESSION # AF220527) ENCODING A LIGHT-HARVESTING CHLOROPHYLL A/B-BINDING PROTEIN (LHCB1) IN UNDERGROUND ADVENTITIOUS BUDS OF LEAFY SPURGE (EUPHORBIA ESULA L.)

Authors: Anderson, James; Horvath, David

Submitted to: Plant Physiology Plant Gene Register Electronic Submission
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2000
Publication Date: 7/1/2000
Citation: Anderson, J.V., Horvath, D.P. 2000. Isolation of a cDNA Clone (Accession # AF220527)Encoding a Light-harvesting Chlorophyll a/b-binding Protein (Lhcb1) in Underground Adventitious Buds of Leafy Spurge(Euphorbia esula L.). PGR00-052)Plant Gene Register. 122:1457.

Interpretive Summary: Our cDNA library was made from 3-day induced (defoliated), underground adventitious buds (the root buds) of leafy spurge. Messenger RNA was used to make the library. Thus, this library represents the genes that are being expressed in that tissue at the time of RNA extraction. We are able to identify which gene products are being expressed by sequencing individual clones isolated from the cDNA library. When we sequenced cDNA clone 13A, we found that it has high sequence identity to genes that bind to chlorophyll a and b. These proteins make large protein complexes in the chloroplast which help the plant to capture light energy. We have positively identified clone 13A as a family member of the type I, light-harvesting chlorophyll a/b binding proteins that function in the chloroplast to help capture light energy. We have also used this cDNA clone to show that the gene encoding this protein is turned-on when leafy spurge plants are defoliated. This causes more of the protein to be generated in the remaining plant tissue. As a result, we think that the foliar tissues (the above ground leaves) produce a signal that regulates the amount of light-harvesting chlorophyll a/b binding protein that is produced in leafy spurge.

Technical Abstract: We have isolated and characterized a cDNA clone encoding a light-harvesting chlorophyll a/b binding protein. The clone was randomly picked from a cDNA library made from mRNA isolated from 3-day induced (defoliated), underground adventitious buds of Euphorbia esula L. (leafy spurge). Sequence to the ORF shows the best identity match with Tomato Lhcb1. Based on current nomenclature, we have termed this clone as Lhcb1*Ee1. Lhcb1*Ee1 is a member of a multigene family and is upregulated in 3-day induced, underground adventitious buds of E. esula. We propose that a signal from the foliar tissue may regulate the expression of Lhcb1*Ee1 in underground adventitious buds.