LAM-1 and FAT genes control development of the leaf blade in Nicotiana sylvestris

• Published in: The Plant cell Vol. 5; no. 9; pp. 1029 - 1038
• Main Author: McHale, N.A
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.09.1993
• Subjects: ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; Biological and medical sciences; Body fat; Cell division; Cell lines; Developmental biology; DIFERENCIACION CELULAR; DIFFERENCIATION CELLULAIRE; FEUILLE; Fundamental and applied biological sciences. Psychology; GENE RECESSIF; GENES RECESIVOS; Genetic mutation; HOJAS; Leaf blade; MESOFILO; Mesophyll; Mesophyll cells; MESOPHYLLE; MORFOGENESIS; MORPHOGENESE; MUTACION INDUCIDA; MUTANT; MUTANTES; MUTATION PROVOQUEE; NICOTIANA; Plant cells; Plant growth. Development of the storage organs; Plant physiology and development; Plants; Vegetative apparatus, growth and morphogenesis. Senescence; Nicotiana; Mitosis; Plant leaf; Meristem; Morphogenesis; Phenotype; Regulation(control); Dicotyledones; Angiospermae; Development; Spermatophyta; Solanaceae; Mutation
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.5.9.1029

Leaf primordia of the lam-1 mutant of Nicotiana sylvestris grow normally in length but remain bladeless throughout development. The blade initiation site is established at the normal time and position in lam-1 primordia. Anticlinal divisions proceed normally in the outer L1 and L2 layers, but the inner L3 cells fail to establish the periclinal divisions that normally generate the middle mesophyll core. The lam-1 mutation also blocks formation of blade mesophyll from distal L2 cells. This suggests that LAM-1 controls a common step in initiation of blade tissue from the L2 and L3 lineage of the primordium. Another recessive mutation (fat) was isolated in N. sylvestris that induces abnormal periclinal divisions in the mesophyll during blade initiation and expansion. This generates a blade approximately twice its normal thickness by doubling the number of mesophyll cell layers from four to approximately eight. Presumably, the fat mutation defines a negative regulator involved in repression of periclinal divisions in the blade. The lam-1 fat double mutant shows radial proliferation of mesophyll cells at the blade initiation site. This produces a highly disorganized, club-shaped blade that appears to represent an additive effect of the lam-1 and fat mutations on blade founder cells