Shoot Development II: Genetics WUSCHEL gene phenotype
{"Image DocumentName": "Shoot Development II: Genetics WUSCHEL gene phenotype", "Image ImageDescription": "Wild Type. Wild type SAM. Wuschel means bushy looking plant. Wuschel mutants have a bushy appearance due to a start and stop growth pattern of the shoot apical meristem. The apical meristem is initiated in shoot tips of wuschel mutants but it fails to develop into an organized SAM. WUS gene mutations result in premature termination of vegetative meristems. WUS expressing cells are required to identify overlying neighbors as stem cells. See:  See:  Older notes: WUSCHEL gene is required to maintain the identity of shoot meristem cells. Wus floral meristems terminate prematurely in a central stamen. Wus stem cells appear to undergo differentiation. WUS gene is expressed in inner portion of the central zone of the meristem. Self perpetuation of the shoot meristem is essential for the repetitive initiation of shoot structures during plant development. In Arabidopsis shoot meristem maintenance is disrupted by recessive mutations in the WUSCHEL (WUS) gene. The defect is evident at all developmental stages and is restricted to shoot and floral meristems, whereas the root meristem is not affected. Results suggest that the WUS gene is specifically required for central meristem identity of shoot and floral meristems to maintain their structural and functional integrity. Source:  WUSCHEL is essential to properly organize a shoot meristem in the embryo. Postembryonically, wus mutants produce defective shoot meristems initiated repetitively, but terminate prematurely. Primordia initiate ectopically across the flat mutant apices and often new shoot meristems instead of organs are initiated. Wus phenotype is plants that terminate growth after producing a few leaves. Flat thin meristems. Interpreted as a depletion of proliferative cells at the SAM. Secondary meristems form resulting in hundreds of rosette leaves. STOP AND GO pattern of growth. WUS normal gene restrains cell differentiation, and thus maintains pool of proliferative cells. The wus mutant removes restraint of cell proliferation. This causes SAM meristem cells to be recruited before they can replenish themselves, leaving the SAM as a flat mass of cells. Wus mutant phenotype is a flat SAM lacking SAM organization\u2026 because the proliferative cells of L1, L2 and L3 have been used up for organ formation. In other words, the pace of organ formation is greater than the pace of SAM meristematic cell replacement in the L1, L2 and L3. WUSCHEL gene is required for meristem integrity in Arabidopsis. WUSCHEL gene (wild type or normal) restrains differentiation at the shoot apex. This allows SAM cell formation to keep pace with differentiation. Wus mutant phenotype: Flat apical meristems, with periodic resumption of meristematic activity. Whole plant consists of bunches of leaves with floral stems with bunches of leaves with floral stems, etc. SAM integrity is lost with the wus mutant gene because L1, L2 and L3 cannot produce cells fast enough to keep up with the pace of organ formation. wus SAM. wus mutant.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}