Transcripts of MYB-like genes respond to phosphorous and nitrogen deprivation in Arabidopsis.
In Arabidopsis thaliana (L.) Heynh., AtPhr2 and AtNsr1 encode proteins with MYB-like and alpha-helical domains. They resemble CrPsr1, a nuclear-localized MYB protein that is critical for acclimation to phosphorous (P) starvation in the alga Chlamydomonas reinhardtii. Reverse transcription-polymerase chain reaction analysis of the first unique exons indicated that AtPhr2 mRNA increased as early as 6 h after P deprivation (-P), whereas nitrogen deprivation (-N) had no effect. The AtNsr1 mRNA level increased exclusively under -N, an increase first noted by 2 days in -N. In spite of P- and N-specific effects on expression of AtPhr2 and AtNsr1 there appeared to be P-N cross-talk at the whole-plant level. Total non-secreted acid phosphatase activity increased under both -P and -N within 2 days of deprivation. Further, the pho2-1/pho2-1 mutant, reported to be a phosphate accumulator, showed no increase in AtPhr2 mRNA in response to -P and a 70% reduction in the response of AtNsr1 mRNA to -N. Consistent with this pattern, there was no increase in acid phosphatase activity in pho2-1/pho2-1 plants deprived of P or N. However, when deprived of P, pho2-1/pho2-1 plants accumulated much higher levels of nitrate. T-DNA disruption of AtNsr1 resulted in altered expression of at least one nitrate transporter (AtNRT2.5). Further evidence of cross-talk between N and P responses was altered expression of N-responsive genes in pho2-1/pho2-1.
Todd
Christopher D
CD
Department of Biochemistry and Interdisciplinary Plant Group, University of Missouri-Columbia, Columbia, MO 65211, USA.
Zeng
Peiyu
P
Huete
Alicia M Rodriguez
AM
Hoyos
Mary Elizabeth
ME
Polacco
Joe C
JC
D000135:Acid Phosphatase / Q000096:biosynthesis; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics*; D002874:Chromosome Mapping; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism; D016415:Sequence Alignment; D013997:Time Factors
D029681:Arabidopsis Proteins; C496227:Nsr1 protein, Arabidopsis; C496226:Phr2 protein, Arabidopsis; D012333:RNA, Messenger; D018749:RNA, Plant; D010758:Phosphorus; D000135:Acid Phosphatase; D009584:Nitrogen