Institutional Publications

Permanent URI for this collectionhttps://ndkr-library.nipgr.ac.in/handle/123456789/11

Browse

Author: search.filters.author.Gupta, Kapuganti JagadisSubject: search.filters.subject.ethylene

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Polyamine induction in postharvest banana fruits in response to NO donor SNP occurs via L-arginine mediated pathway and not via competitive diversion of S-adenosyl-L-methionine
    (MDPI AG, 2019) Lokesh, Veeresh; Manjunatha, Girigowda; Hegde, Namratha S.; Bulle, Mallesham; Puthusseri, Bijesh; Gupta, Kapuganti Jagadis; Neelwarne, Bhagyalakshmi
    Nitric oxide (NO) is known to antagonize ethylene by various mechanisms; one of such mechanisms is reducing ethylene levels by competitive action on S-adenosyl-L-methionine (SAM)—a common precursor for both ethylene and polyamines (PAs) biosynthesis. In order to investigate whether this mechanism of SAM pool diversion by NO occur towards PAs biosynthesis in banana, we studied the effect of NO on alterations in the levels of PAs, which in turn modulate ethylene levels during ripening. In response to NO donor sodium nitroprusside (SNP) treatment, all three major PAs viz. putrescine, spermidine and spermine were induced in control as well as ethylene pre-treated banana fruits. However, the gene expression studies in two popular banana varieties of diverse genomes, Nanjanagudu rasabale (NR; AAB genome) and Cavendish (CAV; AAA genome) revealed the downregulation of SAM decarboxylase, an intermediate gene involved in ethylene and PA pathway after the fifth day of NO donor SNP treatment, suggesting that ethylene and PA pathways do not compete for SAM. Interestingly, arginine decarboxylase belonging to arginine-mediated route of PA biosynthesis was upregulated several folds in response to the SNP treatment. These observations revealed that NO induces PAs via l-arginine-mediated route and not via diversion of SAM pool.
  • Thumbnail Image
    Item
    Nitric oxide is essential for the development of aerenchyma in wheat roots under hypoxic stress
    (John Wiley & Sons, 2017) Wany, Aakanksha; Kumari, Aprajita; Gupta, Kapuganti Jagadis
    In response to flooding/waterlogging, plants develop various anatomical changes including the formation of lysigenous aerenchyma for the delivery of oxygen to roots. Under hypoxia, plants produce high levels of nitric oxide (NO) but the role of this molecule in plant-adaptive response to hypoxia is not known. Here, we investigated whether ethylene-induced aerenchyma requires hypoxia-induced NO. Under hypoxic conditions, wheat roots produced NO apparently via nitrate reductase and scavenging of NO led to a marked reduction in aerenchyma formation. Interestingly, we found that hypoxically induced NO is important for induction of the ethylene biosynthetic genes encoding ACC synthase and ACC oxidase. Hypoxia-induced NO accelerated production of reactive oxygen species, lipid peroxidation, and protein tyrosine nitration. Other events related to cell death such as increased conductivity, increased cellulase activity, DNA fragmentation, and cytoplasmic streaming occurred under hypoxia, and opposing effects were observed by scavenging NO. The NO scavenger cPTIO (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt) and ethylene biosynthetic inhibitor CoCl2 both led to reduced induction of genes involved in signal transduction such as phospholipase C, G protein alpha subunit, calcium-dependent protein kinase family genes CDPK, CDPK2, CDPK 4, Ca-CAMK, inositol 1,4,5-trisphosphate 5-phosphatase 1, and protein kinase suggesting that hypoxically induced NO is essential for the development of aerenchyma.