Genetic variation among species, races, forms and inbred lines of lac insects belonging to the genus Kerria (Homoptera, Tachardiidae)

The lac insects (Homoptera: Tachardiidae), belonging to the genus Kerria, are commercially exploited for the production of lac. Kerria lacca is the most commonly used species in India. RAPD markers were used for assessing genetic variation in forty-eight lines of Kerria, especially among geographic races, infrasubspecific forms, cultivated lines, inbred lines, etc., of K. lacca. In the 48 lines studied, the 26 RAPD primers generated 173 loci, showing 97.7% polymorphism. By using neighbor-joining, the dendrogram generated from the similarity matrix resolved the lines into basically two clusters and outgroups. The major cluster, comprising 32 lines, included mainly cultivated lines of the rangeeni form, geographic races and inbred lines of K. lacca. The second cluster consisted of eight lines of K. lacca, seven of the kusmi form and one of the rangeeni from the southern state of Karnataka. The remaining eight lines formed a series of outgroups, this including a group of three yellow mutant lines of K. lacca and other species of the Kerria studied, among others. Color mutants always showed distinctive banding patterns compared to their wild-type counterparts from the same population. This study also adds support to the current status of kusmi and rangeeni, as infraspecific forms of K. lacca

Scientific Reports

Not AvailableFlax (Linum usitatissimum) is a cool season crop commercially cultivated for seed oil and stem fibre production. A comprehensive characterization of the heat shock factor (HSF) candidate genes in flax can accelerate genetic improvement and adaptive breeding for high temperature stress tolerance. We report the genome-wide identification of 34 putative HSF genes from the flax genome, which we mapped on 14 of the 15 chromosomes. Through comparative homology analysis, we classified these genes into three broad groups, and sub-groups. The arrangement of HSF-specific protein motifs, DNA-binding domain (DBD) and hydrophobic heptad repeat (HR-A/B), and exon-intron boundaries substantiated the phylogenetic separation of these genes. Orthologous relationships and evolutionary analysis revealed that the co-evolution of the LusHSF genes was due to recent genome duplication events. Digital and RT-qPCR analyses provided significant evidence of the differential expression of the LusHSF genes in various tissues, at various developmental stages, and in response to high-temperature stress. The co-localization of diverse cis-acting elements in the promoters of the LusHSF genes further emphasized their regulatory roles in the abiotic stress response. We further confirmed DNA-binding sites on the LusHSF proteins and designed guide RNA sequences for gene editing with minimal off-target effects. These results will hasten functional investigations of LusHSFs or assist in devising genome engineering strategies to develop high-temperature stress tolerant flax cultivars

Scientific Reports

Not AvailableRetting of bast fibres requires removal of pectin, hemicellulose and other non-cellulosic materials from plant stem tissues by a complex microbial community. A microbial retting consortium with high-efficiency pectinolytic bacterial strains is effective in reducing retting-time and enhancing fibre quality. We report comprehensive genomic analyses of three bacterial strains (PJRB 1, 2 and 3) of the consortium and resolve their taxonomic status, genomic features, variations, and pan-genome dynamics. The genome sizes of the strains are ~3.8?Mb with 3729 to 4002 protein-coding genes. Detailed annotations of the protein-coding genes revealed different carbohydrate-degrading CAZy classes viz. PL1, PL9, GH28, CE8, and CE12. Phylogeny and structural features of pectate lyase proteins of PJRB strains divulge their functional uniqueness and evolutionary convergence with closely related Bacillus strains. Genome-wide prediction of genomic variations revealed 12461 to 67381 SNPs, and notably many unique SNPs were localized within the important pectin metabolism genes. The variations in the pectate lyase genes possibly contribute to their specialized pectinolytic function during the retting process. These findings encompass a strong foundation for fundamental and evolutionary studies on this unique microbial degradation of decaying plant material with immense industrial significance. These have preponderant implications in plant biomass research and food industry, and also posit application in the reclamation of water pollution from plant materials

The Crop Journal

Not AvailableCorchorus capsularis (white jute) and C. olitorius (dark jute) are the two principal cultivated species of jute that produce natural bast fiber of commercial importance. We have identified 4509 simple sequence repeat (SSR) loci from 34,163 unigene sequences of C. capsularis to develop a non-redundant set of 2079 flanking primer pairs. Among the SSRs, trinucleotide repeats were most frequent (60%) followed by dinucleotide repeats (37.6%). Annotation of the SSR-containing unigenes revealed their putative functions in various biological and molecular processes, including responses to biotic and abiotic signals. Eighteen expressed gene-derived SSR (eSSR) markers were successfully mapped to the existing single-nucleotide polymorphism (SNP) linkage map of jute, providing additional anchor points. Amplification of 72% of the 74 randomly selected primer pairs was successful in a panel of 24 jute accessions, comprising five and twelve accessions of C. capsularis and C. olitorius, respectively, and seven wild jute species. Forty-three primer pairs produced an average of 2.7 alleles and 58.1% polymorphism in a panel of 24 jute accessions. The mean PIC value was 0.34 but some markers showed PIC values higher than 0.5, suggesting that these markers can efficiently measure genetic diversity and serve for mapping of quantitative trait loci (QTLs) in jute. A primer polymorphism survey with parents of a wide-hybridized population between a cultivated jute and its wild relative revealed their efficacy for interspecific hybrid identification. For ready accessibility of jute eSSR primers, we compiled all information in a user-friendly web database, JuteMarkerdb (http://jutemarkerdb.icar.gov.in/) for the first time in jute. This eSSR resource in jute is expected to be of use in characterization of germplasm, interspecific hybrid and variety identification, and marker-assisted breeding of superior-quality jute

Studies on factors influencing node culture establishment during <i style="mso-bidi-font-style: normal">in vitro</i> shoot multiplication from mature<i style="mso-bidi-font-style: normal"> Schleichera oleosa </i>(Lour.) Oken tree

102-109Schleichera oleosa (Lour.) Oken is a preferred tree-host of kusmi form of lac insect, Kerria lacca, which produces superior quality lac resin of commercial interest. Very low success rate of clonal multiplication of this tree is one of the major bottlenecks for supply of quality planting material for lac cultivation. <i style="mso-bidi-font-style: normal">In vitro multiplication of axillary buds although promise to produce large-scale clones of high-yielding lac hosts, establishment of aseptic node culture is one of the critical steps in standardization of micropropagation from mature S. oleosa plant. The seasonal influence on bud emergence, heavy microbial contaminations and phenolic exudations are the important factors observed in the present study that limits the establishment of axillary bud cultures in <i style="mso-bidi-font-style: normal">S. oleosa. Predominant fungal and bacterial contaminants were identified through morpho-cytological and DNA sequence analysis. The Murashige and Skoog’s (MS) medium with 1.0 mg/L  BAP and 1.0 mg/L silver nitrate showed best (83.33±13.61%) shoot initiation. Sub-culturing and elongation of the proliferated microshoots were possible on filter-paper-bridge soaked in liquid MS medium with 0.5-1.0 mg/L BAP, instead of agar-gelled MS media. Rooting of the axillary bud-derived shoots continued to be the major hurdle to achieve success in developing micropropagation protocol in S. oleosa. <b style="mso-bidi-font-weight: normal"> </span

Tn5 induced mutants of iron assimilation pathway in <i>Cicer Rhizobium </i>strain, COBE13

691-695Siderophore mutants provide an understanding of the iron assimilation pathway under iron limiting conditions. Random Tn5 insertion mutants with varying phenotypes were isolated in Cicer-Rhizobium strain COBE 13. Analysis on siderophore crossfeeding plate identified these mutants as defective in siderophore synthesis, uptake and utilization deficient in siderophore-Fe (III) complex and in regulation

Regeneration of plantlets from nodal explant-derived callus cultures of <i style="mso-bidi-font-style:normal">Albizia lucida</i> Benth.

265-268Albizia lucida Benth. is a forest tree known for timber, gum and tannin, and lac production. Micropropagation of A. lucida can potentially address large-scale production of genetically identical superior genotypes. In the present study, a callus-mediated regeneration protocol has been established from nodal explants of A. lucida for micropropagation. Murashige and Skoog’s (MS) medium supplemented with plant growth regulators like <span style="mso-fareast-font-family:Calibri; mso-ansi-language:EN-IN">thidiazuron (TDZ; 0.5 µM) and <span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-IN">6-benzylaminopurine (BAP; 2.22 mM) were found efficient in callus induction and multiplication. From the multiplied greenish and compact organogenic calli, shoots were regenerated best on MS media consisting BAP (8.88 mM), NAA (1-napthaleneacetic acid; 0.54 mM ) and AgNO3 (5.89 mM). The excised microshoots were rooted efficiently on ½ MS medium supplemented with IBA (indole butyric acid; 9.8 m<i style="mso-bidi-font-style: normal">M) and BAP (0.11 m<i style="mso-bidi-font-style: normal">M). The rooted shoots were acclimatized in polybags containing garden soil, sand and FYM (1:1:1) and then transferred into the open. About 66.67% of the plants survived in the end. The genetic fidelity of the regenerated plantlets was found identical to the mother plant using SRAP primers. </span

Genetic relationships among fruit cultivars and host plants of Indian lac insect in ber (<i style="mso-bidi-font-style: normal">Ziziphus mauritiana </i>Lam.) revealed by RAPD and ISSR markers

170-177The genetic relationship among 26 fruit cultivars of Zizizphus mauritiana Lam. (ber), 6 high resin-yielding lac insect hosts of <i style="mso-bidi-font-style: normal">Z. mauritiana and 2 other Ziziphus spp. used as lac hosts was compared using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) primers with an aim to identify genetically similar cultivars for utilization in fruit as well as in lac production. RAPD (15) and ISSR primers (11) employed in the study revealed 98.82 and 98.86% polymorphisms, respectively among all the ber accessions used. The study revealed that 11 fruit cultivars had &gt;50% genetic similarity with 6 high-yielding lac host genotypes. The UPGMA dendrogram and principal coordinate analysis clustered 11 fruit cultivars and the lac hosts within same cluster. The AMOVA analysis revealed very low genetic variations among the groups of fruit cultivars and high-yielding lac hosts, but high genetic variations within accessions of the groups. The results suggest that 11 ber cultivars may be useful not only as a source for fruit harvesting but also as potential high-yielding lac host plants, thus providing lac growers with more options of economic returns than the wild-type hosts presently used

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