RESUMO
BACKGROUND: The application of ribo nucleic acids for molecular studies requires high integrity and quality of extracted total RNA samples. In addition, the need to transfer RNA samples at room temperature without special treatments such as ice and liquid nitrogen storage according to international transport laws highlights the importance of low cost alternative methods such as RNA air-drying, lyophilisation and transportable agents. In this study, the quality and quantity of air-dried RNA samples from leaf, petiole and bark tissues of different olive genotypes using several RNA extraction methods were compared with lyophilized ground leaves and RNAlater-stored tissue samples before precipitation. The quality of RNA and prepared libraries were checked by several techniques including agarose and polyacrylamide gel electrophoresis, Agilent quality control, RT-PCR amplification of housekeeping and viral genes and high throughput sequencing. RESULTS: Although RNA value varied amongst cultivars, RNA extraction with TRIzol™ Reagent in fresh extractions and samples stored in RNAlater before RNA extraction resulted in 455.26 ng/µL and 63.46 ng/µL (mean value of cultivars) as the highest RNA concentration averages, respectively. RNA samples extracted by TRIzol™ Reagents and stored for a short term at - 80 °C before air-drying showed the third highest concentration (44.87 ng/µL). The synthesized cDNAs quality for PCR amplification of housekeeping genes (Rbc 1 and Nad 5) and partial genomes of Arabis mosaic virus and Cucumber mosaic virus showed satisfactory results in RNA samples extracted by TRIzol™ Reagents despite its variation amongst cultivars. CONCLUSIONS: Considering the difficulties in the extraction of high quality and quantity RNA in olive for molecular analyses, this study demonstrated that RNA extraction method based on TRIzol™ Reagent can be considered for virobiome studies of both fresh and air-dried samples.
RESUMO
BACKGROUND: In vitro culture of olive, as an economically valuable tree, has fundamentally a genotype-dependant low micropropagation rate which needs to be improved in already established and newly released cultivars. Various plant tissue culture media, planting systems and growth factors were evaluated in two promissing Iranian olive cultivars 'Amin' and 'Meshkat' and the commercial Spanish cultivar 'Arbequina'. RESULTS: The results showed that cultivars have their specific optimal media, i.e. 'Amin' in the MS with 4 mg/L zeatin, 'Arbequina' in the OM with 1 mg/L zeatin, and 'Meshkat' in the OM and MS with 2 mg/L zeatin, which produced significantly a higher number of axillary shoots than other media. The results also indicated a significant improvement in the growth indices of 'Amin' (number of axillary shoots) when cultured using periodical mini bioreactor (PMB) in the VS medium. In comparison with VS, OM did not reveal any significant differences when both culturing systems (PMB and semi-solid media (SSM)) were used. Regarding the effect of carbon source and light intensity, mannitol and 2000 cd sr m-2 greatly enhanced 'Arbequina' growth indices (main shoot length and growth quality). The results of genetic stability of callus induced shoots (CIS) and meristem induced shoots (MIS) revealed that 2C DNA value assessed by partec flow cytometery (FCM) had 0.01, 0.03 and 0.08 pg discrepencies in 'Amin', 'Arbequina' and 'Meshkat', repectively. The Amplified Fragment Length Polymorphism (AFLP) results also indicated that the cultivars were classified regardless of the micropropagation origin (CIS or MIS), except for 'Arbequina'. The AFLP findings showed that 'Arbequina' had the highest dispersal (7-38%) in CIS and MIS, while the Iranian cultivar of 'Meshkat' (5-9%) had the highest stability. CONCLUSIONS: This study indicated the importance of in vitro growth parameters for improving the micropropagation indices of olive cultivars. It showed that optimized protocols (OM, PMB, zeatin, mannitol and 2000 cd sr m-2) co-produced larger calli resulting in indirect organogenesis. Based on FCM and AFLP analysis, it can be concluded that true-to-typeness of micropropagated olive was cultivar-dependent.
RESUMO
Rose cultivars with blue flower color are among the most attractive breeding targets in floriculture. However, they are difficult to produce due to the low efficiency of transformation systems, interactive effects of hosts and vectors, and lengthy processes. In this study, agroinfiltration-mediated transient expression was investigated as a tool to assess the function of flower color genes and to determine appropriate host cultivars for stable transformation in Rosa hybrida. To induce delphinidin accumulation and consequently to produce blue hue, the petals of 30 rose cultivars were infiltrated with three different expression vectors namely pBIH-35S-CcF3'5'H, pBIH-35S-Del2 and pBIH-35S-Del8, harbouring different sets of flower color genes. The results obtained showed that the ectopic expression of the genes was only detected in three cultivars with dark pink petals (i.e. 'Purple power', 'High & Mora' and 'Marina') after 6-8 days. The high performance liquid chromatography analyses confirmed delphinidin accumulation in the infiltrated petals caused by transient expression of CcF3'5'H gene. Moreover, there were significant differences in the amounts of delphinidin among the three cultivars infiltrated with the three different expression vectors. More specifically, the highest delphinidin content was detected in the cultivar 'Purple power' (4.67 µg g-1 FW), infiltrated with the pBIH-35S-Del2 vector. The expression of CcF3'5'H gene in the infiltrated petals was also confirmed by real time PCR. In conclusion and based on the findings of the present study, the agroinfiltration could be regarded as a reliable method to identify suitable rose cultivars in blue rose flower production programs.
