Chickpea is an important cool season legume crop. The breeding efforts in chickpea are often hampered due to the narrow genetic base. Availability of diverse germplasm is an essential requirement for ...any crop improvement programme. This can facilitate development of desirable gene combinations and subsequently the improved cultivars. In any marker-assisted selection (MAS) programme, study of parental polymorphism using QTL linked markers is a pre-requisite for screening of desired genotypes. Any such study involving use of markers chosen randomly can only tell the diversity of the parents, but does not guarantee success of the MAS. The present study was undertaken to study the suitability of the SSR markers from the
QTL-hotspot
region linked with drought tolerance related traits in different genetic background. The study of polymorphism of the
QTL-hotspot
linked SSR markers NCPGR127, NCPGR21, TAA170, ICCM0249, STMS11, TR11 and GA24 between drought tolerant genotype ICC-4958 and remaining 32 chickpea genotypes revealed that most of the genotypes had monomorphic alleles as that of ICC-4958, while only a few genotypes showed polymorphic alleles. The markers that are found polymorphic between ICC-4958 and other chickpea genotypes can be used directly for foreground selection in MAS as they are mapped in the
QTL-hotspot
region. However, in cases where these are monomorphic, additional markers from
QTL-hotspot
region need to be screened. Besides validating the suitability of these markers, we also validated SSR markers that can be used for the background selection. Of the 21 SSR markers, 15 were found polymorphic between ICC-4958 and other genotypes suggesting their usefulness in the background selection.
A set of 50 rice genotypes comprising landraces, local selections, and improved varieties were characterized using simple sequence repeat（SSR） and inter simple sequence repeat（ISSR） markers to study ...genetic diversity and population structure. Following unweighted pair group method with arithmetic mean based clustering using binary data of polymorphic markers, the genotypes were grouped into 5 clusters and 11 sub-clusters, whereas population structure analysis separated 50 rice genotypes into 5 sub-populations. Grouping of rice genotypes showed better resemblance with the pedigree information of the genotypes. Both genetic diversity and population structure analysis separated majority of the improved varieties from landraces and local selections. Some of the SSR markers amplified unique alleles which were specific to a particular genotype and could distinguish them from the rest. The results indicate that these rice genotypes exhibit a higher genetic diversity and can be very useful in rice improvement program.
The rice blast caused by the fungus
Magnaporthe oryzae
is one of the most devastating diseases of rice and can lead to complete failure of the crop under severe cases. The first step in breeding for ...blast resistance in rice is therefore to identify the novel sources of resistance and cataloguing different blast resistant genes in these genotypes. In the present study, a set of 37 rice genotypes comprising of landraces, advanced breeding lines and released varieties were first characterized for blast resistance under epiphytotic conditions and subsequently different blast resistant genes were catalogued with the help of markers tightly linked to these genes. A total of 22 different blast resistant genes were catalogued in these genotypes. Lot of diversity was found to be present for different genes in the rice genotypes studied. In addition, a set of 2–3 markers were identified which could distinguish genotypes of a particular geographic area from each other. The results are useful for identifying the right combination of genotypes in the resistance breeding programme.
► Clonal fidelity of banana regenerants from six different in vitro subculture generations and in the explant suckers was studied. ► Both ISSR and REMAP molecular markers revealed high degree of ...monomorphism till 8th generation. ► On epigenetic stability analysis two out of fifteen eighth subculture generation samples showed a methylation sensitive band. ► The investigation confirmed that the micropropagation of banana up to the eighth subculture generation show low variation.
The present work was undertaken to investigate clonal fidelity of banana (
Musa acuminata cv. Grand Naine) regenerants from six different
in vitro subculture generations and in the explant suckers by using ISSR and REMAP molecular markers. Both types of markers revealed high degree of monomorphism. Very low variation was observed up to the eighth subculture generation with polymorphic bands being low in both ISSR (0.96%) and REMAP (0.95%) markers. Epigenetic stability was studied by DNA methylation analysis of the eighth subculture generation samples. Single 570
bp methylation sensitive band was absent in two of the fifteen
MspI predigested samples, while it was present in
HpaII predigested and undigested samples. The results of the investigation confirmed that the micropropagation of banana up to the eighth subculture generation show low variation.
Leaf rust is one of the most destructive diseases of wheat causing huge economic losses throughout the world. Several leaf rust resistance genes have been identified and genetically mapped, some of ...which have also been cloned including the adult plant resistance gene
Lr34
. Selection of wheat genotypes carrying
Lr34
can be accomplished with the help of expression of a morphological marker leaf tip necrosis (LTN) which is linked with
Lr34
. However, recording of LTN under field conditions is time and labor intensive thereby slowing down the process of selection of desirable genotypes. Use of molecular markers which are tightly linked to
Lr34
can be more efficient in precise identification of lines carrying this gene in a short span of time. We selected a total of seven such markers that were earlier reported to be linked with
Lr34
. The objective of the study was to assess the suitability of these markers in distinguishing Indian bread wheat genotypes carrying
Lr34
from those which lacked
Lr34
. The haplotype analysis suggested that one STS marker (csLV34) and two gene specific markers (
cssfr2
and
cssfr5
) could distinguish wheat genotypes carrying
Lr34
from those lacking it. Use of these markers in breeding program can accelerate the speed of selection of desirable genotypes.
A New Abscisic Acid Catabolic Pathway Zhou, Rong; Cutler, Adrian J.; Stephen J. Ambrose ...
Plant physiology,
01/2004, Letnik:
134, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We report the discovery of a new hydroxylated abscisic acid (ABA) metabolite, found in the course of a mass spectrometric study of ABA metabolism in Brassica napus siliques. This metabolite reveals a ...previously unknown catabolic pathway for ABA in which the 9′-methyl group of ABA is oxidized. Analogs of (+)-ABA deuterated at the 8′-carbon atom and at both the 8′- and 9′-carbon atoms were fed to green siliques, and extracts containing the deuterated oxidized metabolites were analyzed to determine the position of ABA hydroxylation. The results indicated that hydroxylation of ABA had occurred at the 9′-methyl group, as well as at the 7′- and 8′-methyl groups. The chromatographic characteristics and mass spectral fragmentation patterns of the new ABA metabolite were compared with those of synthetic 9′-hydroxy ABA (9′-OH ABA), in both open and cyclized forms. The new compound isolated from plant extracts was identified as the cyclized form of 9′-OH ABA, which we have named neophaseic acid (neoPA). The proton nuclear magnetic resonance spectrum of pure neoPA isolated from immature seeds of B. napus was identical to that of the authentic synthetic compound. ABA and neoPA levels were high in young seeds and lower in older seeds. The open form (2Z,4E)-5-(1R,6S)-1-Hydroxy-6-hydroxymethyl-2, 6-dimethyl-4-oxo-cyclohex-2-enyl-3-methyl-penta-2, 4-dienoic acid, but not neoPA, exhibited ABA-like bioactivity in inhibiting Arabidopsis seed germination and in inducing gene expression in B. napus microspore-derived embryos. NeoPA was also detected in fruits of orange (Citrus sinensis) and tomato (Lycopersicon esculentum), in Arabidopsis, and in chickpea (Cicer arietinum), as well as in drought-stressed barley (Hordeum vulgare) and B. napus seedlings.
In this report, two different types of quinoxaline derivatives have been developed with an idea that these molecules are composed of planar structure with extensive π‐delocalization. Accordingly, ...compounds such as 9‐bromoacenaphtho 1,2‐bquinoxaline (3), 4‐(acenaphtho 1,2‐b quinoxalin‐9‐yl) benzaldehyde (5), 11‐bromodipyrido 3,2‐a:2′,3′‐c phenazine (3′) and 4‐(dipyrido 3,2‐a:2′,3′‐c phenazin‐11‐yl) benzaldehyde (5′) were prepared by a sonication method. In order to prove these compounds as potential anticancer agents, binding studies with calf thymus deoxyribonucleic acid (CT‐DNA) and bovine serum albumin (BSA) have been established by absorption and fluorescence studies. The DNA interaction with prepared compounds shows that quinoxaline (3 and 5) and phenazine derivatives (3′ and 5′) are bind to DNA through intercalation and electrostatic modes. The binding strength of 3′ and 5′ with DNA found to be stronger than other two derivatives (3 and 5). The magnitude of 5 and 5′ exhibits 10‐fold more binding efficacy with protein BSA than compound 3′ but compound 3 did not show any binding efficacy with BSA. The MTT (3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) analysis reveals that 5′ exhibits highly selective cytotoxicity profile in HeLa cell line and moderate cytoselectivity in human epithelial colorectal adenocarcinoma cells (Caco‐2) cell line with respect to the normal cell line. However, compound 3 showed best potency and selectivity in Caco‐2 cells.
Novel Acenaphtho quinoxaline and Dipyridophenazine analogues were synthesized using a simple and efficient procedure. Biomolecular interaction was carried out by absorption and fluorescence studies. These results suggest that the quinoxaline derivatives bind to DNA through intercalation and electrostatic mode. The significant hypochromism in fluorescence observed from BSA binding study indicates the strong binding of these compounds with BSA which helps in transport of the compounds in biological systems. These compounds are also exhibited high potency and selectivity in cancer cells than normal cells.
Cytological and molecular investigations were undertaken for parent and progeny derived from a trispecific line 2(Gossypium arboreum × G. anomalum) × G. hirsutum var. BWR, which was crossed with ...G. hirsutum var. JLH168. Cytomorphological analysis of the F1 (G. arboreum × G. anomalum), its amphidiploid and progeny from trispecies hybrid showed distorted ploidy segregation with monovalents to hexavalents and high intergenomic (small A2 and large B1) allosynthetic chromosome pairing. Microsatellite analysis identified three fragments associated with G. arboreum and G. anomalum and six fragments associated with G. hirsutum in derivates of the trispecies line × G. hirsutum var. JLH168. Inter‐Retrotransposon Amplified Polymorphism (IRAP) analysis revealed fragments of G. arboreum and G. anomalum, only in F1 and amphidiploid. Chromosomal association and microsatellite analysis of three progeny genotypes (i.e. haploid, hexaploid and tetraploid no. 1) confirmed that they share multigenomic background from the three cotton species (A2, AhDh and B1 genome). The interspecific hybrid cotton genotypes studied are likely to be useful for the introgression of genes from diploid species to commercial upland cultivars.
Isotopically labeled ABA and its hydroxylated metabolites, 7’-, 8’- and 9’- hydroxy ABA, were supplied to microspore-derived embryos of
Brassica napus cv Hero. All compounds included expression of ...oleosin and fatty acid elongase genes and increased the accumulation of triacylglycerois and very long chain fatty acids.
Developing seeds of
Brassica napus contain significant levels of ABA and products of oxidation at the 7′- and 9′-methyl groups of ABA, 7′- and 9′-hydroxy ABA, as well stable products of oxidation of the 8′-methyl group, phaseic acid and dihydrophaseic acid. To probe the biological roles of the initially formed hydroxylated compounds, we have compared the effects of supplied ABA and the hydroxylated metabolites in regulating oil synthesis in microspore-derived embryos of
B. napus, cv Hero that accumulate long chain fatty acids. Uptake into the embryos and metabolism of each of the hormone metabolites was studied by using deuterium labeled analogs. Supplied ABA, which was rapidly metabolized, induced expression of oleosin and fatty acid elongase genes and increased the accumulation of triacylglycerols and very long chain fatty acids. The metabolites 7′- and 9′-hydroxy ABA had similar effects, with the 9′-hydroxy ABA having even greater activity than ABA. The principal catabolite of ABA, 8′-hydroxy ABA, also had hormonal activity and led to increased oil synthesis but induced the genes weakly. These results indicate that all compounds tested could be involved in lipid synthesis in
B. napus, and may have hormonal roles in other ABA-regulated processes.
Pigeonpea is an important protein rich legume food crop grown in marginal environments of the world. Environmental stress, pests and disease cause massive yield losses due to limited genetic ...diversity of pigeonpea in the primary gene pool. Genetic manipulation is becoming an important method for pigeonpea improvement. In the present study, a reproducible and highly efficient plant-regeneration protocol in pigeonpea varieties, viz., 'Phule Rajeshwari' and 'Vipula' was developed. Multiple shoot induction was achieved using leaf and apical meristem with attached leaf as explant by use of various concentrations and combinations of growth regulators. Optimum embryogenic callus induction from leaf explant was observed on Murashige and Skoogs medium supplemented with 2.0 mg/l thidiazuron. Apical meristem with attached leaf explants showed early shoot initiation, high frequency of callusing (100%), and shoot regeneration (100%) as compared with leaf explant in both varieties. In vitro rooting (93.33%) was obtained within 10 days on MS medium supplemented with 2.0 mg/l indole butyric acid. The in vitro rooted plantlets were successfully established in polycarbonated polyhouse with 80% survival rate. This optimized regeneration protocol can be efficiently used for genetic transformation in pigeonpea.
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