Cloning and characterization of NBS-LRR resistance gene analogues of Musa spp. and their expression profiling studies against Pratylenchus coffeae

Resistance gene analogues (RGAs) were isolated from two banana cultivars viz., Karthobiumtham and Rose using degernate primers designed from the conserved motifs of different plant resistance genes. A total of 40 sequences were hit with various R genes, of which 20 sequences were having uninterrupted open reading frame (ORFs). Based on the conserved domains like P loop, internal kinase 2, kinase 3a and hydrophobic domain motifs of the deduced amino acid sequences were grouped as NBS-LRR class of resistant genes. The phylogentic analysis of RGAs showed that all the Musa RGAs are grouped under non-TIR branch and grouped into six distinct Musa RGA cluster. To investigate the expression profile of the RGAs, specific primers were designed for one representative RGA from each RGA cluster and it was found that C1 and C5 were induced upon root lesion nematode infection in the resistant (cv. Karthobiumtham) and not in susceptible (cv.Nendran) cultivar. C6 was expressed only in resistant cultivar not in susceptible one. But there was no change in the expression of C2 and C3 in both resistant and susceptible cultivars. These results indicate that in depth study on C1, and C5 RGAs will be helpful for further improvement of P. coffeae resistance in banana.Keywords: Banana, P. coffeae, resistance gene analogues, expression levelAfrican Journal of Biotechnology Vol. 12(27), pp. 4256-426

Electrophysiological responses of banana pseudostem weevil, Odoiporus longicollis Olivier (Coleoptera: Curculionidae) to methyl jasmonate, 1-hexanol and host plant extract

53-57The banana pseudostem weevil (BSW), Odoiporus longicollis Olivier (Coleoptera: Curculionidae) is one of the most destructive pests of banana and plantains. Our laboratory bioassay studies showed that out of 50 host plants related volatile chemicals screened against BSW, only methyl jasmonate (MeJA) and 1-hexanol was electrophysiologically and behaviourally active. Here, we investigated the influence of host plant extract (HPE) on two semiochemicals, namely methyl jasmonate (MeJA) and 1-hexanol, both independently and in combination, in the electroantennogram (EAG) response in BSW. The results showed that HPE alone elicited greater EAG response only in males suggesting that males involved predominantly in the host plant selection. Addition of HPE to MeJA increased significantly higher EAG response in females and the response was insignificant in males. Similarly, the addition of HPE to 1-hexanol evoked higher response in females but decreased antennal activity was recorded in males compared to HPE alone. The HPE showed additive effect on MeJA and 1-hexanol in their EAG responses only in female BSW. The result also revealed that 1-hexanol+HPE blend exhibited enhanced EAG response compared to 1-hexanol alone in both sexes

Yield and nutrient rontent of chilli (Capsicum annuum L.) in responu to sources of P ilnd levels of P and N

The highest yield of chilli dry pods (2770 kg ha-1) was obtained by the application of 120, 60 and 35 kg N, P2O5 and K2O ha-1. The response to N and P application was linear up to 120 and 60 kg ha-1 N and P2O5, respectively. The protein content of dry pod increased in the higher levels of N and the highest value (12.2.5%) was recorded at 120 kg ha-1. N and P application increased protein and mineral contents of dry pods. Among the sources of P, rock phosphate registered maximum calcium content compared to single super phosphate. The efficiency of incubated rock phosphate was similar to that of single super phosphate. However, rock phosphate with phosphobacteria did not enhance yield. Farm yard manure incubated rock phosphate proved to be a cheaper source of phosphatic fertilizer for soils with higher pH (>8). &nbsp

Electrophysiological responses of banana pseudostem weevil,Odoiporus longicollis Olivier (Coleoptera: Curculionidae) tomethyl jasmonate, 1-hexanol and host plant extract

The banana pseudostem weevil (BSW), Odoiporus longicollis Olivier (Coleoptera: Curculionidae) is one of the mostdestructive pests of banana and plantains. Our laboratory bioassay studies showed that out of 50 host plants related volatilechemicals screened against BSW, only methyl jasmonate (MeJA) and 1-hexanol was electrophysiologically and behaviourallyactive. Here, we investigated the influence of host plant extract (HPE) on two semiochemicals, namely methyl jasmonate(MeJA) and 1-hexanol, both independently and in combination, in the electroantennogram (EAG) response in BSW. The resultsshowed that HPE alone elicited greater EAG response only in males suggesting that males involved predominantly in the hostplant selection. Addition of HPE to MeJA increased significantly higher EAG response in females and the response wasinsignificant in males. Similarly, the addition of HPE to 1-hexanol evoked higher response in females but decreased antennalactivity was recorded in males compared to HPE alone. The HPE showed additive effect on MeJA and 1-hexanol in their EAGresponses only in female BSW. The result also revealed that 1-hexanol+HPE blend exhibited enhanced EAG responsecompared to 1-hexanol alone in both sexes

Evaluation of biorationals against thrips (Sdothrips cardamomi Ramk.) and shoot and capsule borer (Conogethes punctiferalis Guen.) in cardamom

A field experiment was conducted to evaluate the efficacy of biorationals in the management of thrips and shoot and capsule borer of cardamom. Among the biorationals evaluated, fish oil insecticidal soap (FOIS) (Na) 2.5% + tobacco extract 2.5% significantly reduced the damage caused by thrips. None of the treatments is effective for the control of shoot and capsule borer infestation on the capsules and all the treatments were on par with the control. Spraying quinalphos (0.05%) reduced the damage caused by thrips (6%) and increased the yield (391 g plant-1). Foraging activity of honey bees was highest in control plots. &nbsp

Varietal evaluation of black pepper (Piper nigrum L.) for yield, quality and anthracnose disease resistance in Idukki District, Kerala

Fourteen accessions of black pepper were evaluated at the Cardamom Research Station, Pampadumpara for yield, quality and disease resistance. Out of the fourteen cultivars, CuI. 239 (Panniyur-5) recorded the highest wet (906.5 g) and dry (310.1 g) yield of berries per plant. The maximum volatile oil (5.06%) and oleoresin (9.4%) contents in dry berries were observed in CuI. 5128 and Panniyur-1, respectively. A positive correlation existed between the number of spikes and berries per plant and yield. However, yield and quality characters are negatively correlated, though not significant. The results showed that Panniyur-5 is the most suitable black pepper variety for high range conditions of Idukki District. &nbsp

Evaluation of high yielding accessions of small cardamom (Elettaria cardamomum Maton) for suitability in the high ranges of Idukki District

Ten high yielding small cardamom accessions were collected from RRS, Mudigere; ICRI, Saklespur and CRS, Pampadumpara and evaluated for their suitability in Idukki District, Kerala. M-1 and PV -1 were found to be high yielding varieties since both of them recorded the highest yield consistently for four consecutive years. M-l was relatively tolerant to thrips infestation. The biometrical traits such as plant height, tiller number, panicle number, panicle length and seed number showed high positive correlation with yield. These characters are likely to be the ideal selection criteria in small cardamom. &nbsp

Management of anthracnose disease (Colletotrichum gloeosporioides (Penz) Penz & Sac.) of black pepper (Piper nigrum L.) in the high ranges of Idukki District, Kerala

Evaluation of contact and systemic fungicides for the management of anthracnose disease(caused by Colletotrichum gloeosporioides) on black pepper (Piper nigrum) at Idukki District (Kerala)indicated that the incidence of the disease on leaves and spikes was significantly lower invines treated with a combination fungicide containing carbendazim +  mancozeb 0.1% followedby carbendazim 0.1%. The dry berry yield was also significantly highest (742.7 g vine-1) invines treated with carbendazim + mancozeb 0.1%. &nbsp

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Not AvailableSoil moisture deficit stress is one of the most important abiotic stresses limiting the production and productivity of banana (Musa spp.). Plant responses to drought stress are regulated at both the transcriptional and post-transcriptional levels. As post-transcriptional gene regulators, microRNAs (miRNAs) regulate gene expression during drought stress. The present study aimed to identify drought-responsive miRNAs in an expressed sequence tag (EST) library of drought-stressed banana and to study their expression in a drought-tolerant banana cultivar, ‘Saba’, subjected to soil moisture deficit stress. In silico prediction resulted in the identification of three miRNAs (miR156, miR169, and miR2118) whose expression was confirmed using real-time qPCR assays with the respective complementary DNAs (cDNAs) synthesised in multiplex stem-loop-primed reverse-transcription reactions. The selection of a suitable reference miRNA for this study was carried out using six genes, which included the traditional Musa reference gene for 25S rRNA. miR399 was selected as the reference miRNA, based on its constant level of expression in various tissues and sample types. Additional regulatory roles for miR169 on expression of the dehydrin and aquaporin genes in banana were investigated using qPCR assays in drought-stressed leaf samples collected at different times during stress. The results suggested that miR169, miR156, and miR2118 were up-regulated during soil moisture deficit stress, and also that miR169 had an indirect, transcription-level role in regulating dehydrin and aquaporin gene expression. The aquaporin gene exhibited more prominent expression compared to dehydrin in banana during drought stress.ICAR, ICAR-NRC

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Not AvailableSensitive techniques of molecular biology, such as identification of differentially expressed genes, transcriptional profiling etc., require a high quality RNA in suitable quantities. Isolation of good quality RNA fro1n banana pulp and peel tissues is troublesome and challenging owing to rich phenolic compounds and polysaccharides that coprecipitate with nucleic acids. Interaction of phenols with nucleic acids leads to oxidation and degradation of RN A making it unsuitable for downstream processes. We have developed a protocol to isolate good quality RNA from banana fruit pulp and peel tissues This involves two precipitation steps with sodium acetate with I 00 per cent ethanol and reducing the precipitation time which led to the reduction in loss of RNA and risk of degradation. The protocol developed is simple, fast and can extract 81.85 and 40.54 μgig of pulp and peel tissues, respectively. The absorbance ranged from I. 9-2.0 at the ratio of260/280 indicating very high quality of RNA suitable for molecular analyses. RNA purity was confirmed through reverse transcription-polymerase chain reaction (RT-PCR) by using J3-1,3 glucanase primer pair. The clear banding pattern obtained in RT-PCR analysis revealed that RNA isolated through this protocol could be used for further downstrea1n processes.ICAR, ICAR-NRC