Phosphorus stress in common bean: root transcript and metabolic responses.
Phosphorus (P) is an essential element for plant growth. Crop production of common bean (Phaseolus vulgaris), the most important legume for human consumption, is often limited by low P in the soil. Functional genomics were used to investigate global gene expression and metabolic responses of bean plants grown under P-deficient and P-sufficient conditions. P-deficient plants showed enhanced root to shoot ratio accompanied by reduced leaf area and net photosynthesis rates. Transcript profiling was performed through hybridization of nylon filter arrays spotted with cDNAs of 2,212 unigenes from a P deficiency root cDNA library. A total of 126 genes, representing different functional categories, showed significant differential expression in response to P: 62% of these were induced in P-deficient roots. A set of 372 bean transcription factor (TF) genes, coding for proteins with Inter-Pro domains characteristic or diagnostic for TF, were identified from The Institute of Genomic Research/Dana Farber Cancer Institute Common Bean Gene Index. Using real-time reverse transcription-polymerase chain reaction analysis, 17 TF genes were differentially expressed in P-deficient roots; four TF genes, including MYB TFs, were induced. Nonbiased metabolite profiling was used to assess the degree to which changes in gene expression in P-deficient roots affect overall metabolism. Stress-related metabolites such as polyols accumulated in P-deficient roots as well as sugars, which are known to be essential for P stress gene induction. Candidate genes have been identified that may contribute to root adaptation to P deficiency and be useful for improvement of common bean.
Hernández
Georgina
G
Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, 66210 Cuernavaca, Mor., Mexico. gina@ccg.unam.mx
Ramírez
Mario
M
Valdés-López
Oswaldo
O
Tesfaye
Mesfin
M
Graham
Michelle A
MA
Czechowski
Tomasz
T
Schlereth
Armin
A
Wandrey
Maren
M
Erban
Alexander
A
Cheung
Foo
F
Wu
Hank C
HC
Lara
Miguel
M
Town
Christopher D
CD
Kopka
Joachim
J
Udvardi
Michael K
MK
Vance
Carroll P
CP
D000222:Adaptation, Physiological / Q000235:genetics*; D008401:Gas Chromatography-Mass Spectrometry; D020869:Gene Expression Profiling; D017343:Genes, Plant; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D027805:Phaseolus / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010758:Phosphorus / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism
D014157:Transcription Factors; D010758:Phosphorus