Chitinase, beta-1,3-glucanase, osmotin, and extensin are expressed in tobacco explants during flower formation.
Sequence analysis of five gene families that were isolated from tobacco thin cell layer explants initiating floral development [Meeks-Wagner et al. (1989). Plant Cell 1, 25-35] showed that two encode the pathogenesis-related proteins basic chitinase and basic beta-1,3-glucanase, while a third encodes the cell wall protein extensin, which also accumulates during pathogen attack. Another sequence family encodes the water stress-induced protein osmotin [Singh et al. (1989). Plant Physiol. 90, 1096-1101]. We found that osmotin was also induced by viral infection and wounding and, hence, could be considered a pathogenesis-related protein. These genes, which were highly expressed in explants during de novo flower formation but not in explants forming vegetative shoots [Meeks-Wagner et al. (1989). Plant Cell 1, 25-35], were also regulated developmentally in day-neutral and photoresponsive tobacco plants with high expression levels in the roots and moderate- to low-level expression in other plant organs including flowers. An unidentified gene family, FB7-4, had its highest level of expression in the basal internodes. Our findings indicate that these genes, some of which are conventionally considered to encode pathogen-related proteins, also have a complex association with normal developmental processes, including the floral response, in healthy plants.
Neale
A D
AD
Division of Plant Industry, Commonwealth Scientific and Industrial Research Organization, Canberra, Australia.
Wahleithner
J A
JA
Lund
M
M
Bonnett
H T
HT
Kelly
A
A
Meeks-Wagner
D R
DR
Peacock
W J
WJ
Dennis
E S
ES
D000595:Amino Acid Sequence; D001483:Base Sequence; D002688:Chitinases / Q000235:genetics*; D005786:Gene Expression Regulation; D043326:Glucan 1,3-beta-Glucosidase; D006023:Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics*; D010947:Plants, Toxic; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D001617:beta-Glucosidase / Q000235:genetics*
D006023:Glycoproteins; D010940:Plant Proteins; C005488:extensin protein, plant; C073139:osmotin protein, Nicotiana tabacum; D002688:Chitinases; D001617:beta-Glucosidase; D043326:Glucan 1,3-beta-Glucosidase