Induction of nitrate reductase activity and mRNA accumulation in rice

Halim bin Hamat, . Induction of nitrate reductase activity and mRNA accumulation in rice. pp. 13-22. ISSN 0128-0686

Western blot analysis using barley DADH-nitrate reductase antisera revealed that nitrate-induced rice seedling leaf extracts contain a cross reacting polypeptide of 115 000 dalton. Nitrate-induced rice seedling leaf extracts appeared to contain both NADH- and NAD(P)H-nitrate reductase activity. The NADH-nitrate reductase activity was detected 2 h after the addition of nitrate and increased rapidly to 24 h. The activity continued to increase at a slower rate until about 48 h and declined thereafter. The results on the nitrate content in leaf showed a similar pattern to the NADH- nitrate reductase activity. The NAD(P)H-nitrate reductase activity was detected within 1 h after induction with nitrate which increased rapidly reaching a maximum activity within 3 h. Both pHBH1 and pHBH2 clones (accompanying paper) hybridized to a 3.2 kb mRNA but the appearance of the mRNA following nitrate induction was different. Induction studies using unique sequences of each clone as the probe revealed that clone pHBH1 hybridized to a 3.2 kb mRNA. Upon induction by nitrate it showed kinetics similar to NADH-nitrate reductase activity. The 3.2 kb mRNA was detected after 1 h and peaked at 6 h after induction and declined from 12 h to 24 h. The NADH-nitrate reductase activity increased rapidly during the first 4 h and peaked at 48 h after nitrate induction. Clone pHBH2 hybridized to a 3.2 kb mRNA. Upon induction by nitrate it showed kinetics similar to NAD(P)H-nitrate reductase activity. The 3.2 kb mRNA was detected very early reached maximum 30 min after nitrate induction and declined very rapidly. No 3.2 kb mRNA was detected from 6 h to 24 h after induction. The NAD(P)H-nitrate reductase activity was inducible by nitrate. The activity increased very rapidly reaching maximum within 3 h declined after 5 h and very little from 10 h to 72 h. These results suggested that clone pHBH1 codes for NADH-nitrate reductase while clone pHBH2 codes for NAD(P)H-nitrate reductase. The results also indicated that the regulation at transcriptional levels is different between the NADH and NAD(P)H-nitrate reductase.

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Abstract

Western blot analysis using barley DADH-nitrate reductase antisera revealed that nitrate-induced rice seedling leaf extracts contain a cross reacting polypeptide of 115 000 dalton. Nitrate-induced rice seedling leaf extracts appeared to contain both NADH- and NAD(P)H-nitrate reductase activity. The NADH-nitrate reductase activity was detected 2 h after the addition of nitrate and increased rapidly to 24 h. The activity continued to increase at a slower rate until about 48 h and declined thereafter. The results on the nitrate content in leaf showed a similar pattern to the NADH- nitrate reductase activity. The NAD(P)H-nitrate reductase activity was detected within 1 h after induction with nitrate which increased rapidly reaching a maximum activity within 3 h. Both pHBH1 and pHBH2 clones (accompanying paper) hybridized to a 3.2 kb mRNA but the appearance of the mRNA following nitrate induction was different. Induction studies using unique sequences of each clone as the probe revealed that clone pHBH1 hybridized to a 3.2 kb mRNA. Upon induction by nitrate it showed kinetics similar to NADH-nitrate reductase activity. The 3.2 kb mRNA was detected after 1 h and peaked at 6 h after induction and declined from 12 h to 24 h. The NADH-nitrate reductase activity increased rapidly during the first 4 h and peaked at 48 h after nitrate induction. Clone pHBH2 hybridized to a 3.2 kb mRNA. Upon induction by nitrate it showed kinetics similar to NAD(P)H-nitrate reductase activity. The 3.2 kb mRNA was detected very early reached maximum 30 min after nitrate induction and declined very rapidly. No 3.2 kb mRNA was detected from 6 h to 24 h after induction. The NAD(P)H-nitrate reductase activity was inducible by nitrate. The activity increased very rapidly reaching maximum within 3 h declined after 5 h and very little from 10 h to 72 h. These results suggested that clone pHBH1 codes for NADH-nitrate reductase while clone pHBH2 codes for NAD(P)H-nitrate reductase. The results also indicated that the regulation at transcriptional levels is different between the NADH and NAD(P)H-nitrate reductase.

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Item Type:	Article
Additional Information:	5 graphs; 35 ref. Summary (En Malay)
AGROVOC Term:	ORYZA SATIVA
AGROVOC Term:	NITRATOS
AGROVOC Term:	OXIDORREDUCTASAS
AGROVOC Term:	ARN MENSAJERO
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:55
URI:	http://webagris.upm.edu.my/id/eprint/20057

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