The Arabidopsis CPSF30‐L gene plays an essential role in nitrate signaling and regulates the nitrate transceptor gene NRT1.1

Abstract

Plants have evolved sophisticated mechanisms to adapt to fluctuating environmental nitrogen availability. However, more underlying genes regulating the response to nitrate have yet to be characterized. We report here the identification of a nitrate regulatory mutant whose mutation mapped to the Cleavage and Polyadenylation Specificity Factor 30 gene (CPSF30-L). In the mutant, induction of nitrate-responsive genes was inhibited independent of the ammonium conditions and was restored by expression of the wild-type 65 kDa encoded by CPSF30-L. Molecular and genetic evidence suggests that CPSF30-L works upstream of NRT1.1 and independently of NLP7 in response to nitrate. Analysis of the 3'-UTR of NRT1.1 showed that the pattern of polyadenylation sites was altered in the cpsf30 mutant. Transcriptome analysis revealed that four nitrogen-related clusters were enriched in the differentially expressed genes of the cpsf30 mutant. Nitrate uptake was decreased in the mutant along with reduced expression of the nitrate transporter/sensor gene NRT1.1, while nitrate reduction and amino acid content were enhanced in roots along with increased expression of several nitrate assimilatory genes. These findings indicate that the 65 kDa protein encoded by CPSF30-L mediates nitrate signaling in part by regulating NRT1.1 expression, thus adding an important component to the nitrate signaling network.

The polyadenylation factor FIP1 is important for plant development and root responses to abiotic stresses

“…In recent years, it has been proven that differential poly(A) usage and/or polyadenylation site selection is an important regulatory mechanism in plants (Shen et al ., ; Wu et al ., , ; Sherstnev et al ., ; De Lorenzo et al ., ; Deng and Cao, ; Li et al ., ). The majority of plant loci possess several poly(A) sites with at least one located at the end of the defined 3′‐UTR (Shen et al ., ; Wu et al ., , ; Fu et al ., ); however, by adding alternative poly(A)‐sites in other locations than the 3′‐UTR, in introns, in exons or even in the 5′‐UTR, new transcripts that encode different proteins or regulatory RNAs can be generated.…”

“…Recently, a T‐DNA insertional mutant in the FIP1 gene has been reported. Similar to mutations in CPSF‐30L , another component of the polyadenylation machinery, this fip1 allele had a reduced induction of nitrate‐responsive genes upon treatment with nitrate (Li et al ., ; Wang et al ., ). In addition, fip1 seedlings show a reduction in nitrate content resulting from a deregulation of nitrate uptake genes and a different content of amino acids (Wang et al ., ).…”

Ornithine δ‐aminotransferase is critical for floret development and seed setting through mediating nitrogen reutilization in rice

“…During the grain filling stage, most grain nitrogen (as much as 80%) is derived from mature leaves and shoots by reutilization (Yoneyama et al, 2016). The regulatory pathways of nitrogen absorption and assimilation have been extensively reported (Sun et al, 2014b;Xu et al, 2016;Li et al, 2017). However, little information has been available regarding the importance of nitrogen reutilization.…”

The long noncoding RNA T5120 regulates nitrate response and assimilation in Arabidopsis

“…The three nlp7 mutant lines ( nlp7‐1 , nlp7‐2 , and nlp7‐4 containing NRP–YFP) (Castaings et al ., ; Xu et al ., ) and the transgenic lines (p NLP7 ::NLP7−GFP/ nlp7‐1 and p 35S ::NLP7−GFP/ nlp7‐1 ) (Marchive et al ., ) were previously described. The mutant lines chl1‐5 (Ho et al ., ), cipk8‐1 (salk_139697) (Hu et al ., ), nrg2‐2 (salk_079096) (Xu et al ., ), cpsf30‐2 (Li et al ., ) were previously described. Transgenic lines carrying p 35S :: T5120 were obtained by floral dipping (Clough & Bent, ) of the WT and nlp7‐4 mutant.…”

“…The primary nitrate response is defined as the short‐term effects of nitrate exposure (Medici & Krouk, ; Zhao et al ., ). Transcriptional analysis and experimental validation indicate that the expression of > 1000 genes including NRT2.1 , NIA1 , and NIR is altered after nitrate treatment (Wang et al ., , ; Scheible et al ., ; Xu et al ., ; Li et al ., ). Recently, some genes containing NRT1.1 , NLP6/7 , LBD37/38/39 , SPL9 , TGA1/4 , CIPK8/23 , NRG2 , CPSF30‐L , and FIP1 have been identified as important regulators in primary nitrate response (Alvarez et al ., ; Medici & Krouk, ; Xu et al ., ; Wang C. et al ., ; Wang Y. Y. et al ., ; Fredes et al ., ).…”