Browsing by Author "Muralikrishna, K.S."
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Item 5-Azacytidine promotes the induction of embryogenic calli and somatic embryos from transverse thin cell layer (tTCL) cultures in coconut(2024) Keezhath Thazha Kuniyil Amritha; Muralikrishna, K.S.; Jasmin Habeeb; Chandran, K.P.; Paulraj, S.; Rajesh, M.KCoconut (Cocos nucifera L.) is highly recalcitrant to in vitro interventions. There is a need to overcome various bottlenecks to standardize a repeatable protocol for in vitro regeneration in coconut to meet the requirements of quality planting materials. Epigenetic processes, especially DNA methylation, are known to assay crucial roles in regulating genes controlling plant growth and development, especially somatic embryogenesis. In this study, we demonstrate that the supplementation of 5-azacytidine (5-azaC), a demethylating agent, in the coconut tissue culture media can enhance the formation of embryogenic calli, somatic embryos, and plantlet regeneration from transverse thin sections of mature zygotic embryos. Transverse thin cell layer (tTCL) sections of zygotic embryos were cultured onto Y3 medium supplemented with different concentrations of 5-azaC (0, 10, 15, and 20 μM), auxins (2,4-D, picloram and atrazine; 75 and 100 μM) and thidiazuron (TDZ;4.5 μM). Explants were exposed to constant 5-azaC and reduced auxin concentration in subsequent sub-culturing. Our results indicated supplementing 15 μM 5-azaC, in combination with picloram (75 μM) and TDZ (4.54 μM), improved the percentage of callusing (95.8%) and formation of embryogenic calli (87.5%), and formation of somatic embryos (4.7) and plantlets (4.0) per explant in comparison with control having 80.8%, 75.0%, 1.6 and 0.67, respectively from tTCL sections of mature zygotic embryos. The results will form the basis for designing more efficient coconut tissue culture protocols.Item Biotechnological Approaches(2017) Anitha Karun; Rajesh, M.K.; Muralikrishna, K.S.; Sajini, K.K.; Chowdappa, P.Item Coconut Biotechnology:New Vistas(2017-12) Rajesh, M.K.; Sajini, K.K.; Muralikrishna, K.S.; Anitha KarunItem A comparative study of three different methods of shoot meristem excision for induction of embryogenic calli in coconut(2016) Bhavyashree, U.; Lakshmi Jayaraj, K.; Fayas, T.P.; Muralikrishna, K.S.; Sajini, K.K.; Rajesh, M.K.; Anitha KarunItem Cryopreservation of arecanut (Areca catechu L.) pollen(2017-11) Anitha Karun; Sajini, K.K.; Muralikrishna, K.S.; Rajesh, M.K.; Florent EngelmannItem DNA extraction method from endosperm of Areca concinna Thwaites, a wild relative of arecanut(2018) Muralikrishna, K.S.; sabana, A.A.; Midhuna, K.; Anitha Karun; Rajesh, M.K.Item Effect of elevated CO2 and temperature on oxidative stress and antioxidant enzymes activity in coconut (Cocosnucifera L.) seedlings(2014-11) John Sunoj, V.S.; Naresh Kumar, S.; Muralikrishna, K.S.Increasing atmospheric CO2 concentration is one of the factors driving climate change. We have investigated the individual effect of elevated CO2 and temperature on oxidative stress and antioxidant enzymes activity in coconut (Cocosnucifera L.) seedlings. Three cultivars (WCT, LCT and COD) and two hybrids (WCT 9 COD and COD 9 WCT) were grown in six open top chambers (OTCs) and responses were analyzed after three years. In two OTCs the CO2 was set at 550 and 700 lmol mol-1 and control chamber had ambient level of 393 lmol mol1. In two separate OTCs, air temperature was elevated by 2 C above the ambient control chamber. Remaining two chambers served as chamber control. Elevated CO2 and temperature increased the activities of superoxide dismutase and catalase , whereas it reduced polyphenol oxidase activity. On the other hand, peroxidase (POX) activity was decreased in elevated temperature, while it increased under elevated CO2 conditions. The POX activity and membrane stability index (MSI) were positively correlated. By virtue of greater MSI and lower MDA content, WCT and hybrid COD 9 WCT were observed to be tolerant to oxidative stress among the five cultivars under elevated CO2 and temperature conditions. These cultivars may adapt better to changing climates.Item Elevated carbon dioxide and temperature reduce stomatal density in coconut (cocos nucifera L.)(2009) Muralikrishna, K.S.; Naresh Kumar, S.; John Sunoj, V.S.; Kasturi Bai, K.V.Item Embryo culture to rescue rare coconut types(2017-05) Anitha Karun; Muralikrishna, K.S.; Rajesh, M.K.Item Enhancement of callogenesis from plumular explants of coconut (Cocos nucifera) via exogenous supplementation of amino acids and casein hydrolysate(2023) Aparna, V.; Neema, M.; Chandran, K.P.; Muralikrishna, K.S.; Anitha KarunItem Immature embryo culture in wild Areca spp(2017) Muralikrishna, K.S.; Rajesh, M.K.; Sajini, K.K.; Nagaraja, N.R; Ananda, K.S.; Anitha KarunItem In vitro assay for screening of Areca spp. for Phytophthora resistance(2018) Muralikrishna, K.S.; Sharadraj, K.M; Gangaraj, K.P.; Nagaraja, N.R.; Anitha Karun; Rajesh, M.K.; Chowdappa, P.Item In vitro retrieval via embryo rescue of 'Mohachao Narel', a sweet endosperm coconut from Maharashtra(2017) Anitha Karun; Sajini, K.K.; Rajesh, M.K.; Muralikrishna, K.S.; Samsudeen, K.; Ajith Kumar, P.; Nagwekar, D.D.Item Initiation of coconut cell suspension culture from shoot meristem derived embryogenic calli: A preliminary study(2016) Bhavyashree, U.; Lakshmi Jayaraj, K.; Muralikrishna, K.S.; Sajini, K.K.; Rajesh, M.K.Item Maintenance of embryogenic potential of calli derived from embryonic shoot of West Coast Tall cv. of coconut(Cocos nucifera L.)(2015-08) Rachana, K.E.; Muralikrishna, K.S.; Sajini, K.K.; Rajesh, M.K.; Anitha KarunMaintenance of embryogenic potential of calli is important as the totipotency is often lost in a short time in vitro. This caters to the need for year round availability of somatic embryos in a regenerable state. In the present study, 14 media combinations, with either 2,4-D or picloram as auxin source, were tested for maintaining embryogenic calli obtained from embryonic shoot explants of coconut. Irrespective of type and concentration of auxins, callusing was observed in all the media combinations. However, high dose of 2,4-D (above 74.6 μM) in the initial medium resulted in intense browning and lesser percentage of callusing. Embryogenic nature of calli could be maintained to a maximum of 21 weeks in medium supplemented with 2,4-D (74.6 μM) and subsequent culturing into higher concentration of 2,4-D (90.4 μM). Gene expression studies carried out using qRT-PCR revealed that genes such as ECP, GST, LEAFY and WUS were highly expressed in long term embryogenic calli (21 week old) and genes such as SERK, GLP, WRKY and PKL in initial embryogenic calli (21 days old). The study concludes that coconut plumular calli could be maintained for longer periods without compromising on the embryogenic potential of the calli.Item Physio-chemical changes in coconut leaf at different maturity stages(2011) Kasturi Bai, K.V.; Sugatha Padmanabhan; Muralikrishna, K.S.; John Sunoj, V.S.Item Proline may assume greater role in coconut (Cocos nucifera L) adaptation to elevated CO2 and temperature conditions(2009) John Sunoj, V.S.; Naresh Kumar, S.; Muralikrishna, K.S.; Kasturi Bai, K.V.Item Towards establishing a molecular market based accreditation laboratory for coconut hybrids(2018-10) Rajesh, M.K.; Regi Jacob Thomas; Samsudeen, K.; Jesmi Vijayan; Muralikrishna, K.S.