Pollen development and tube growth are affected in the symbiotic mutant of Lotus japonicus, crinkle.
The symbiotic mutant of Lotus japonicus, crinkle (crk), exhibits abnormal nodulation and other alterations in the root hairs, trichomes, and seedpods. Defective nodulation in crk mutant is due to the arrested infection thread growth from the epidermis into the cortex. Here, we describe that crk is also affected in male fertility that causes the production of small pods with few seeds. Under in vitro conditions, pollen germination and tube growth were markedly reduced in the crk mutant. A swollen tip phenotype with disorganized filamentous actin (F-actin) was observed in the mutant pollen tubes after prolonged in vitro culture. During pollen development, the striking difference noted in the mutant was the small size of the microspores that remained spherical. Histological examination of ovule development, as well as outcrosses of the mutant as female to wild type as male, showed no evidence of abnormality in the female gametophyte development. Based on these findings, the Crk gene, aside from its role in the infection process during nodulation, is also involved in male gametophyte development and function. Therefore, this gene represents a connection between nodule symbiosis, polar tip growth, and other plant developmental processes.
Tansengco
Myra L
ML
Department of Biotechnology, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871 Japan.
Imaizumi-Anraku
Haruko
H
Yoshikawa
Makoto
M
Takagi
Shingo
S
Kawaguchi
Masayoshi
M
Hayashi
Makoto
M
Murooka
Yoshikatsu
Y
D000199:Actins / Q000378:metabolism; D035264:Flowers / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D005718:Gametogenesis / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D066298:In Vitro Techniques; D000070116:Lotus / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D009154:Mutation / Q000235:genetics*; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D011058:Pollen / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D012098:Reproduction / Q000235:genetics; D012639:Seeds / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D012733:Sex Differentiation / Q000235:genetics; D013559:Symbiosis / Q000235:genetics*
D000199:Actins