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Projects / Programmes source: ARIS

MOLEKULSKA ANALIZA REGIJE KROMOSOMA, ODGOVORNE ZA RAZVOJ SPOLA PRI HMELJU (Humulus lupulus L.) (Slovene)

Research activity

Code Science Field Subfield
4.03.01  Biotechnical sciences  Plant production  Agricultural plants 

Code Science Field
4.01  Agricultural and Veterinary Sciences  Agriculture, Forestry and Fisheries 
Evaluation (rules)
source: COBISS
Researchers (1)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  22591  PhD Suzana Škof  Biotechnical sciences  Head  2009 - 2012  46 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0481  University of Ljubljana, Biotechnical Faculty  Ljubljana  1626914  66,215 
Significance for science
Hop appears to be well suited to sex determination studies, since it has the benefit of initiating only one set of sex organs, which suggests that genes, which could control the gender differences probably act well in advance of flowering organogenesis. This is in contrast to most of the monoecious and dioecious plant species being used to investigate the molecular basis of sex determination (e.g. cucumber, white campion, asparagus, kiwi), which initiate both male and female sex organs prior to the suppression or abortion of the inappropriate set at a later stage of development. A relatively simple way for dioecious plant species to regulate the development of male and female sex organs would be through differential regulation of the expression of the ABCE floral organ-identity genes, specifically the B and C genes, that are implicated in specifying the identity of the stamen and carpel whorls (Theissen 2001). Differential expression of B and C genes has been demonstrated in a number of plant species showing gender polymorphism (e.g. S. latifolia, R. acetosa), although it is not yet known whether this imply a causal role for B and C genes in gender expression. B and C genes could be expressed in sex specific manner in developing hop flowers, since the inappropriate set of sex organs is never initiated in flowers of either sex (Shephard et al. 2000). Identification and study of expression patterns of the putative ABCE floral organ-identity genes in developing hop floral buds could provide new insights in their possible involvement in sex determination in hop and in other dioecous plants. In our study real-time PCR revealed different expression patterns of putative C gene (Agamous homolog) and putative E gene (Sepallata3 homolog) in female and male flower buds in different developmental stages. Four new DArT markers linked to male sex in hop were identified. These four markers could be directly used in hop breeding programmes for early discrimination of hop seedlings before entering the adult stage to aid breeding programs and for quick selection of planting material. DArT markers due to hybridization platform originate predominantly from genomic regions with genes and are consequently more interesting for discovering sex determination genes in contrast to SSR, ISSR, AFLP and RAPD markers, which originate predominantly from repetitive non-codogenic regions of the genome. Several X- or Y-linked genes are already known and described in different dioecious species (e.g. Silene, papaya), and recently several candidate genes that may have an influence on sex determination in grapevine were found. One DArT marker showed significant similarity with glycosyltransferase-like protein, which has been recently discovered to be located in the region of the flower sex locus in grapevine (Fechter et al. 2012).
Significance for the country
Sex determination in hop is currently limited to phenotypic evaluation in the second year of growth. Only female inflorescences (hop cones) have commercial value. Male plants are only used for breeding purposes and are not wanted in hop gardens due to decreased quality of fertilized hop cones and high probability of unintentional crosses. Earlier sex determination at the seedling stage is desirable for breeding and cultivation of hop: one approach is the use of molecular markers. Since data suggest incomplete linkage to the male character or non-amplification in certain male genotypes in two male markers known, more new markers linked to sex would be helpful in programmes of marker assisted selection. Identification of four new reliable sex linked diagnostic markers is also an economically important acquisition, since it will essentially shorten long-lasting breeding procedures in hop. As well it will reduce costs and enable rapid and more efficient selection of planting material in agronomically important dioecious plants, where plants of one gender have superior agronomic traits to those of the other. The results will be useful not only in Slovenian economy but also in other countries, where hops are grown. Currently, four new DArT male markers are tested for male plants identification in the population of 500 hop seedlings in the breeding programme of the Slovenian Institute of Hop Research and Brewing in Žalec.
Most important scientific results Final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2011, final report, complete report on dLib.si
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