Recent advances in flower color alteration by metabolic manipulation of carotenoid biosynthesis

U hortikulturi je prisutna stalna potreba za ukrasnim biljkama sa novim karakteristikama, gde boja cveta predstavlja jednu od najvažnijih osobina koja određuje njihovu komercijalnu vrednost. Sa razvojem metoda genetičkog inženjeringa otvorena je mogućnost kreiranja biljaka sa željenom bojom cvetova koja se ne može postići klasičnim ukrštanjem ili mutagenezom. Boja cvetova kod biljaka određena je sadržajem tri biljna pigmenta: antocijanina, karotenoida i betalaina. Do sada, najveći napredak postignut je genetičkom modulacijom biosinteze antocijanina. Na ovaj način postignute su nove boje cvetova kod najmanje 50 ukrasnih vrsta, a neki od tih modifikovanih varijeteta su već dugi niz godina u slobodnoj prodaji. Međutim, promena boje cveta manipulacijom biosintetskog puta karotenoida je dokumentovana kod svega nekoliko ukrasnih vrsta i poslednjih godina intenzivirana su istraživanja u tom pravcu. U ovom radu je razmatran potencijal ovog pristupa, sa posebnim osvrtom na rezultate postignute na promeni boje cvetova kod kultivara ljubičice uvodjenjem gena za kapsantin-kapsorubin sintazu.In horticulture, there is a constant need for ornamental plants with new characteristics, where the flower color is one of the most important features that determines their commercial value. With the development of genetic engineering methods, it has been possible to create plants with the desired flower color which cannot be achieved by classical breeding or mutagenesis. The flower color in plants is determined by the content of three plant pigments: anthocyanins, carotenoids and betalains. Up to date, the greatest progress has been made by genetic modulation of anthocyanin biosynthesis. In this way, the new flower colors have been achieved in at least 50 ornamental species, and some of these modified varieties have been on market for many years. However, the alteration of flower color by manipulating the carotenoid biosynthetic pathway has been documented in only a few ornamental species, and the research has been significantly increased last few years. In this paper, the potential of this approach is considered, with special reference to the results achieved on flower color alteration of pansy cultivars by introducing the gene for capsanthin-capsorubin synthase

Elimination of TSWV from Impatiens hawkerii Bull. and regeneration of virus-free plant

The possibility for obtaining virus free plants from Impatiens hawkerii Bull. shoots infected with Tomato spotted wilt virus (TSWV) through meristem-tip culture was examined. TSWV presence in I. hawkerii plants was detected by DAS-ELISA and RT-PCR and identification of the virus was confirmed by sequencing one of the chosen isolate (GenBank Accesion CQ132190). Meristem-tip explants (0.3-1.5 mm) from virus-infected shoots are cultured on MS media supplemented with different concentrations of the cytokinins, CPPU or TDZ (0.01-1.0 mu M), respectively. Using this system, a large number of in vitro shoots could be produced from a single explant. Also, cytokinins showed a stimulatory effect on the length, fresh and dry weights of the newly formed shoots. Plant pigments content in I. hawkerii shoots increased significantly in the presence of cytokinins. Rooting of shoots was spontaneous on the same media. Rooted plantlets were transferred to soil where 97% successfully acclimatized. By DAS-ELISA and RT-PCR, 80% of the in vitro plantlets were shown to be a virus-free. Considering these, the present protocol seems to be an efficient method for in vitro generation of virus-free I. hawkerii plantlets by meristem tip cultures

Primena tehnika in vitro kulture za eliminaciju virusa iz ukrasnih biljaka

Viruses are responsible for numerous epidemics in different crops in all parts of the world. As a consequence of their presence great economic losses are being incurred. In addition to the development of sensitive techniques for detection, identification and characterization of viruses, substantial attention has also been paid to biotechnological methods for their elimination from plants. In this review article, the following biotechnological in vitro culture techniques for virus elimination from ornamental plants are presented: meristem culture, thermotherapy, chemotherapy, cryotherapy or a combination of these methods. The plant species, as well as the type of virus determine the choice of a most suitable method. The state of the art in investigation of virus elimination from Impatiens sp. in Serbia is summarized.Virusi su odgovorni za brojne epidemije na različitim usevima u svim delovima sveta. Posledica njihovog prisustva su velike ekonomske štete, pa osim razvoju osetljivih tehnika za detekciju, identifikaciju i karakterizaciju virusa, velika pažnja se poklanja i biotehnološkim metodama za njihovu eliminaciju. U ovom preglednom radu predstavljene su tehnike in vitro kulture za eliminaciju virusa iz biljnog materijala: kultura meristema, termoterapija, hemoterapija, krioterapija ili kombinacija ovih metoda. Koja će metoda biti primenjena zavisi od biljne vrste, kao i od vrste virusa. U radu je dat pregled istraživanja na eliminaciji virusa iz Impatiens sp. u Srbiji

Elimination of TSWV from Impatiens hawkerii Bull. and regeneration of virus-free plant

The possibility for obtaining virus free plants from Impatiens hawkerii Bull. shoots infected with Tomato spotted wilt virus (TSWV) through meristem-tip culture was examined. TSWV presence in I. hawkerii plants was detected by DAS-ELISA and RT-PCR and identification of the virus was confirmed by sequencing one of the chosen isolate (GenBank Accesion CQ132190). Meristem-tip explants (0.3-1.5 mm) from virus-infected shoots are cultured on MS media supplemented with different concentrations of the cytokinins, CPPU or TDZ (0.01-1.0 µM), respectively. Using this system, a large number of in vitro shoots could be produced from a single explant. Also, cytokinins showed a stimulatory effect on the length, fresh and dry weights of the newly formed shoots. Plant pigments content in I. hawkerii shoots increased significantly in the presence of cytokinins. Rooting of shoots was spontaneous on the same media. Rooted plantlets were transferred to soil where 97% successfully acclimatized. By DAS-ELISA and RT-PCR, 80% of the in vitro plantlets were shown to be a virus-free. Considering these, the present protocol seems to be an efficient method for in vitro generation of virus-free I. hawkerii plantlets by meristem tip cultures