Transcriptomic analysis to reveal the differentially expressed miRNA targets and their miRNAs in response to Ralstonia solanacearum in ginger species

Background Bacterial wilt is the most devastating disease in ginger caused by Ralstonia solanacearum. Even though ginger (Zingiber officinale) and mango ginger (Curcuma amada) are from the same family Zingiberaceae, the latter is resistant to R. solanacearum infection. MicroRNAs have been identified in many crops which regulates plant-pathogen interaction, either through silencing genes or by blocking mRNA translation. However, miRNA’s vital role and its targets in mango ginger in protecting bacterial wilt is not yet studied extensively. In the present study, using the “psRNATarget” server, we analyzed available ginger (susceptible) and mango ginger (resistant) transcriptome to delineate and compare the microRNAs (miRNA) and their target genes (miRTGs). Results A total of 4736 and 4485 differential expressed miRTGs (DEmiRTGs) were identified in ginger and mango ginger, respectively, in response to R. solanacearum. Functional annotation results showed that mango ginger had higher enrichment than ginger in top enriched GO terms. Among the DEmiRTGs, 2105 were common in ginger and mango ginger. However, 2337 miRTGs were expressed only in mango ginger which includes 62 defence related and upregulated miRTGs. We also identified 213 miRTGs upregulated in mango ginger but downregulated in ginger, out of which 23 DEmiRTGS were defence response related. We selected nine miRNA/miRTGs pairs from the data set of common miRTGs of ginger and mango ginger and validated using qPCR. Conclusions Our data covered the expression information of 9221 miRTGs. We identified nine miRNA/miRTGs key candidate pairs in response to R. solanacearum infection in ginger. This is the first report of the integrated analysis of miRTGs and miRNAs in response to R. solanacearum infection among ginger species. This study is expected to deliver several insights in understanding the miRNA regulatory network in ginger and mango ginger response to bacterial wilt.

Penghambatan Enzim Alpha-Glukosidase oleh Daun Mimba (Azadirachta indica) dan Rimpang Temu Mangga (Curcuma mangga)

Type 2 diabetes mellitus is a chronic disease of the digestive system characterized by high blood glucose levels. The main enzyme in carbohydrate metabolism is α-glucosidase. One of the therapeutic approaches to treat T2DM is to make glucose uptake into the blood delayed through inhibition of the α-glucosidase enzyme activity. Neem leaves and mango ginger are reported to reduce blood glucose levels. This study aims to determine the potential inhibitor of neem leaves extract and mango ginger extract and their respective fractions on α-glucosidase activity. Simplicia of neem leaves and mango ginger were macerated using 96% ethanol for 24 hours. The ethanol extract of neem leaves and mango rhizome were fractionated using silica gel 60 GF254 as adsorbent and a combination of ethyl acetate and n-hexane as eluent. The extracts of neem leaves and mango rhizome and fractions of both plants were tested for α-glucosidase inhibition with acarbose as a comparison. The results showed that both plants provided inhibitory activity on α-glucosidase with the lowest IC50 value from the semi-polar fraction of neem leaves about 24.16±4.58 μg/mL. Neem leaves and mango ginger have potential as α-glucosidase inhibitors to treat type 2 diabetes mellitus.

Characterization of Volatile Organic Compounds in Mango Ginger (Curcuma amada Roxb.) from Myanmar

Curcuma amada Roxb. (Zingiberaceae), commonly known as mango ginger because its rhizome and foliar parts have a similar aroma to mango. The rhizome has been widely used in food industries and alternative medicines to treat a variety of internal diseases such as cough, bronchitis, indigestion, colic, loss of appetite, hiccups, and constipation. The composition of the volatile constituents in a fresh rhizome of C. amada is not reported in detail. The present study aimed to screen and characterize the composition of volatile organic compound (VOC) in a fresh rhizome of three C. amada (ZO45, ZO89, and ZO114) and one C. longa (ZO138) accessions originated from Myanmar. The analysis was carried out by means of headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-time-of-flight-mass spectrometry (GC-TOF-MS). As a result, 122 VOCs were tentatively identified from the extracted 373 mass spectra. The following compounds were the ten most highly abundant and broadly present ones: ar-turmerone, α-zingiberene, α-santalene, (E)-γ-atlantone, cuparene, β-bisabolene, teresantalol, β-sesquiphellandrene, trans-α-bergamotene, γ-curcumene. The intensity of ar-turmerone, the sesquiterpene which is mainly characterized in C. longa essential oil (up to 15.5–27.5%), was significantly higher in C. amada accession ZO89 (15.707 ± 5.78a) compared to C. longa accession ZO138 (0.300 ± 0.08b). Cis-α-bergamotene was not detected in two C. amada accessions ZO45 and ZO89. The study revealed between-species variation regarding identified VOCs in the fresh rhizome of C. amada and C. longa.

Unravelling the Differential Expression of Potential microRNAs in Bacterial Wilt-resistant and Susceptible Ginger Species

MicroRNAs (miRNA) have been shown to regulate plant pathogen interaction, by silencing genes, destructing or blocking of the translation of mRNA. However, their role in bacterial wilt, caused by Ralstonia solanacearum in ginger, has not been studied. In the present study, we utilized the transcriptome data from ginger-Ralstonia solanacearum interactions to characterize miRNAs from bacterial wilt-susceptible ginger (Zingiber officinale) and resistant mango ginger (Curcuma amada). The assembled mRNAs were utilized to generate miRNA targets and miRNAs. Considering the alignment results, we located a total of 2926 potential miRNA targets out of which 1551 were upregulated and 1419 were downregulated in ginger. In case of mango ginger, out of 2145 potential miRNA targets, 1506 were upregulated and 1594 were downregulated. In the resistance interactions with mango ginger, 1068 unique target genes were upregulated when compared to control. Gene Ontology (GO) analysis of differentially expressed target genes showed highest enrichment in response to cold, chloroplast and ATP binding in biological, cellular and molecular functions respectively. Nine target genes and their corresponding miRNAs were experimentally validated, which shows significant difference in expression with ginger-Ralstonia solanacearum interactions. The results will be very useful to disease resistant varieties of ginger.