Environmental cues have synergistic or antagonistic regulatory roles on transcription activity and taxanes accumulation in yew, though DBAT activity is less influenced, could be accordingly a rate-limiting enzyme. The current work was undertaken to elucidate the consequences of some environmental cues (i.e., day length, temperature, sunlight and relative humidity) on the expression patterns of TXS, DBAT, BAPT and DBTNBT genes contributed to the taxol biosynthetic pathway along with the accumulation of some taxanes in needles and stems of Taxus baccata over year 2013-2014. In both tissues, light intensity and temperature correlated with the production of 10-DAB III and total taxanes, and TXS activity, while a lack of significant association was deduced for day length and relative humidity. Furthermore, in both tissues, a weak correlation was observed between BAC III and light intensity, temperature, day length and relative humidity, and the corresponding gene, DBAT. Surprisingly, DBAT activity was not co-induced with TXS in both tissues, and remained expressed at basal levels over year, supporting that the conversion of 10-DAB III into BAC III could presumably be a rate limiting step in the taxol biosynthetic pathway. Similar to BAC III, no strong correlation was detected between production of taxol in both tissues and all the meteorological data, while the corresponding genes BAPT and DBTNBT, in some cases, exhibited significant correlated results. Notably, despite higher activities of BAPT and DBTNBT in both tissues over year, taxol production was still in small quantities, probably owing to the low amounts of its precursors rather than low volumes of BAPT and DBTNBT transcripts. The results, altogether, could provide us new insights towards the potential regulatory roles of environmental cues on the production of taxanes in yew trees.

St. John's wort (Hypericum perforatum L.), as the most important medicinal species of the genus Hypericum, is medicinally used for many purposes such as treatment of mild and moderate depression. Considering importance of knowledge on genetic structure of wild relatives of crop plants, the present study was aimed to assess genetic variability among ten wild populations of H. perforatum growing in different climatic regions of Iran via ISSR markers. In general 15 selected primers generated 191 polymorphic fragments with an average of 12 in each primer. According to the UPGMA constructed dendrogram and PCoA, studied populations were classified into four main groups which was, to the some extent, in accordance with their geographical origins. Genetic distances of these populations ranged from 0.109 (Nor and Nowshahr) to 0.345 (Ardebil and Galogah). Also, Nei gene diversity (H e ) values were calculated to be from 0.066 to 0.216 and Shannon's information indices (I) varied from 0.321 to 0.097. Nei's genetic differentiation index (G st ) was high (0.573) indicating the high levels of genetic variation among the studied populations. Finally, the gene flow (N m ) value was found to be 0.372. Obtained information is useful for use of Iranian H. perforatum germplasm for breeding programs and for development of effective conservation strategies.

An in vitro approach to the production of rosmarinic acid (RA), a medicinally important caffeic acid ester, in a cell suspension culture (CSC) of Satureja khuzistanica Jamzad (Lamiaceae) has been investigated for the first time. The CSC was established from friable calli derived from shoot tip explants in Gamborg's B5 liquid medium supplemented with 30 g/L sucrose, 20 mg/L L-glutamine, 200 mg/L casein hydrolysate, 5 mg/L benzyladenine (BA) and 1 mg/L indole-3-butyric acid (IBA). The effect of nitrogen source (KNO 3 and (NH 4 ) 2 SO 4 ) and their different concentrations on the fresh and dry weight (g/L), as well as RA content (mg/g dry weight)were measured. CSC growth measurements indicated a maximum specific cell growth rate of 1.5/day, a doubling time of 7.6 days and a high percentage of cell viability (96.4 %) throughout the growth cycle. Maximum cell fresh weight (353.5 g/L), dry weight (19.7 g/L) and RA production (180.0 mg/g) were attained at day 21 of culture. Cell growth and RA content were affected by nitrogen deficiency. Media containing 8.3 mM of total nitrogen ( of B5 standard medium) led to a minimum cell fresh weight (243.0 g/ L), dry weight (17.4 g/L) and RA content (38.0 mg/g) after 21 days. The established CSC provided useful material for further optimization experiments aimed at a large-scale production of RA.

No abstract

Attempts were made here to apply a modified analytic hierarchy process (AHP) approach based on refinement assay of dominated alternatives in monitoring the most reliable callus maintenance media (supplemented with L-glutamine and Casamino acid) of Taxus baccata callus cultures in terms of five criteria. Generally, regarding stem-derived calli, 6 out of 18 maintenance media were nominated as non-dominated alternatives, and following AHP ranking test Casamino acid-based media (i.e., A12, A15 and A19) were overall nominated as the premiere. Taking leaf-derived calli into account, only L-glutaminebased media in an ascending order of A8, A4, A6, A5, A9 and A3 were introduced as non-dominated alternatives. Such results connote that L-glutamine-based feeding appears to generate more significant results either for continuous calli growth or taxanes production. In contrast, regarding the second explant, stem, both amino acid supplies had fairly equal worth. Our findings, overall, demonstrate promising applications of the proposed AHP method regarding accurate selection of the best callus maintenance cultures of T. baccata for production of different taxanes including paclitaxel, Baccatin III and 10-deacetylbaccatin III. Similarly, this statistical approach could be also applicable for other crops, for instance, for accurate selection of the best callus cultures/media and consequently production improvement of a given plant secondary metabolite/product.