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Title: CLONING AND EXPRESSION OF SHOOTMERISTEMLESS FROM ADVENTITIOUS BUDS OF THE PERENNIAL WEED LEAFY SPURGE.

Author
item VARANASI, VIJAY - NDSU
item Horvath, David

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2005
Publication Date: 3/21/2005
Citation: Varanasi, V., Horvath, D.P. 2005. Cloning and expression of shootmeristemless from adventitious buds of the perennial weed leafy spurge. [Abstract]. Midwestern Society of the American Society of Plant Biology. Page No. 22.

Interpretive Summary: We have cloned and characterized a key gene involved in bud growth and development from the noxious perennial weed leafy spurge. The gene we have cloned is very similar to a group of genes known as the KNOTTED gene family which was originally identified in the model plant Arabidopsis, and was shown to play a significant role in shoot growth and development, and also shown to play a role in leaf formation and organization in plants such as tomato. The gene we have cloned from leafy spurge is most similar to the KNOTTED family gene member known as SHOOTMERISTEMLESS (STM). STM is required for formation and maintenance of the growing shoot tip of the plant, and plants that have mutations in this gene do not form or maintain growing shoots (and thus die). We have found that STM in leafy spurge is not “turned on” to high levels in dormant buds of leafy spurge until they are induced to grow.

Technical Abstract: Leafy spurge (Euphorbia esula L.) was introduced into North America from Eurasia and has spread across the mid-west and northern plains. Leafy spurge has an extensive root system and large number of dormant underground adventitious buds on its lateral roots, making it an ideal plant for studying growth and development of adventitious buds. There are numerous genes responsible for the initiation and maintenance of shoot apical meristems. SHOOTMERISTEMLESS (STM) a key member of the KNOTTED gene family, is one such gene. STM encodes a homeodomain protein and is responsible for maintaining a pool of undifferentiated cells in the central zone of the shoot meristem. The expression or function of STM in dormant buds is not well understood. Our objective was to clone and characterize the expression pattern of STM after induction of adventitious root buds in leafy spurge and throughout different seasons. We designed primers for conserved region of STM and PCR amplified the STM sequence from cDNA derived from growing meristems. The amplified fragment was then used to identify near full length cDNA and genomic clones of STM from respective leafy spurge DNA libraries. It was found that STM was up-regulated in as little as 8 hours after induction and continues to increase in expression through 72 hrs. STM was also found to be minimally down-regulated in eco-dormant crown buds, but rapidly reaches control levels in mid- to late winter.