title: The altered responses of a new mutant long life span 1 to cytokinin in Arabidopsis thaliana.
abstract: Cytokinins are a class of essential plant hormones regulating plant growth and development. Although the two-component phosphorelay pathway of cytokinin has been well characterized, the intact cytokinin responses regulation picture still needs to be fully depicted. Here we report a new mutant, long life span 1 (lls1), which displays dwarf stature, curled leaves, numerous axillary branches and nearly 5-month life span. Exogenous cytokinin could not recover the phenotypes of the mutant. Moreover, mutation in lls1 suppressed the cytokinin-responsive phenotypes, including root and hypocotyl growth inhibition, anthocyanin accumulation, metaxylem promotion in primary root development. The induction of cytokinin-responsive genes, ARR5, AHP5, and CKX3, was also suppressed in lls1. According to quantitative RT-PCR (qRT-PCR) and microarray results, the basal expression of positive factors AHP5, ARR1, and ARR10 were down-regulated, while the negative factors ARR4 and ARR5 were up-regulated. Our results suggested that LLS1 gene might be involved in the regulation of cytokinin signaling. It was mapped to chromosome 4 where no other cytokinin relevant gene has been reported.
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200062, China.
authors.forename: Xinghua
authors.initials: X
authors.lastname: Shao
authors.forename: Ru
authors.initials: R
authors.lastname: Yang
authors.forename: Jingyu
authors.initials: J
authors.lastname: Wang
authors.forename: Qi
authors.initials: Q
authors.lastname: Fang
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Yue
authors.initials: Y
authors.lastname: Sun
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Li
mesh_terms: D000872:Anthocyanins / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D048429:Cell Size; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003583:Cytokinins / Q000494:pharmacology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D056426:Genetic Loci / Q000235:genetics; D018546:Hypocotyl / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D019441:Plant Epidermis / Q000166:cytology / Q000254:growth & development / Q000648:ultrastructure; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000872:Anthocyanins; D003583:Cytokinins; D010937:Plant Growth Regulators