Transcription factors  expressed in soybean roots under drought stress.
To gain  insight into stress-responsive gene regulation in soybean plants, we identified  consensus sequences that could categorize the transcription factors MYBJ7,  BZIP50, C2H2, and NAC2 as members of the gene families myb, bzip, c2h2, and nac, respectively. We also investigated the  evolutionary relationship of these transcription factors and analyzed their  expression levels under drought stress. The NCBI software was used to find the  predicted amino acid sequences of the transcription factors, and the Clustal X  software was used to align soybean and other plant species sequences.  Phylogenetic trees were built using the Mega 4.1 software by neighbor joining  and the degree of confidence test by Bootstrap. Expression level studies were  carried out using hydroponic culture; the experiments were designed in  completely randomized blocks with three repetitions. The blocks consisted of  two genotypes, MG/BR46 Conquista (drought-tolerant) and BR16  (drought-sensitive) and the treatments consisted of increasingly long  dehydration periods (0, 25, 50, 75, and 100 min). The transcription factors  presented domains and/or conserved regions that characterized them as belonging  to the bzip, c2h2, myb, and nac families. Based on  the phylogenetic trees, it was found that the myb, bzip and nac genes are closely related to myb78, bzip48 and nac2 of  soybean and that c2h2 is closely related to c2h2 of Brassica  napus. Expression of all genes was in general increased under drought  stress in both genotypes. Major differences between genotypes were due to the  lowering of the expression of the mybj7 and c2h2 genes in the  drought-tolerant variety at some times. Over-expression or silencing of some of  these genes has the potential to increase stress tolerance.
Universidade Estadual de São Paulo Julio de Mesquita Filho, Jaboticabal, SP, Brasil.
S S
SS
Pereira
F C M
FC
Guimarães
J F C
JF
Carvalho
R
R
Stolf-Moreira
M C N
MC
Oliveira
A A P
AA
Rolla
J R B
JR
Farias
N
N
Neumaier
A L
AL
Nepomuceno
D000595:Amino Acid Sequence; D055864:Droughts; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics* / Q000502:physiology; D016415:Sequence Alignment; D013025:Glycine max / Q000235:genetics* / Q000502:physiology*; D013312:Stress, Physiological / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D010940:Plant Proteins; D014157:Transcription Factors