Nitric oxide regulates shikonin formation in suspension-cultured Onosma paniculatum cells.

Endogenously occurring nitric oxide (NO) is involved in the regulation of shikonin formation in Onosma paniculatum cells. NO generated after cells were inoculated into shikonin production medium reached the highest level after 2 d of culture, which was 16 times that at the beginning of the experiment, and maintained a high level for 6 d. A nitric oxide synthase (NOS) inhibitor, N(omega)-nitro-L-arginine (L-NNA), and a nitrate reductase (NR) inhibitor, sodium azide (SoA), consistent with their inhibition of NO biosynthesis, decreased shikonin formation significantly. This reduction could be alleviated or even abolished by exogenous NO supplied by sodium nitroprusside (SNP), suggesting that the inhibition of NO biosynthesis resulted in decreased shikonin formation. However, when endogenous NO biosynthesis was up-regulated by the elicitor from Rhizoctonia cerealis, shikonin production was enhanced further, showing a dependence on the elicitor-induced NO burst. Real-time PCR analysis showed that NO could significantly up-regulate the expression of PAL, PGT and HMGR, which encode key enzymes involved in shikonin biosynthesis. These results demonstrated that NO plays a critical role in shikonin formation in O. paniculatum cells.

[RAPD analysis on genetic relationships of Erigeron breviscapus germplasm resources].

OBJECTIVE: To investigate the genetic relationships of Erigeron breviscapus at the molecular biology level. METHOD: Thirty seven germplasm resources of E. breviscapus which collected from Yunnan, Sichuang and Guizhou province in 2005 were analyzed by Random amplified polymorphic DNA (RAPD) and cluster analysis based on NTSYS2. RESULT: A total of 10 primers were screened, and 107 bands were amplified, among which 94 (87.85%) bands were found to be polymorphic. Thirty seven germplasm resources of E. breviscapus were clustered into 3 groups at genetic distance 0.36, the I group include in 9 germplasm resources collected from Mile, Qiubei, Luxi, Gejiu, and Yanshan of south east of Yunnan province; the II group included 8 germplasm resources collected from Gucheng, and shangrila of north west of Yunnan province, and Mile and Qiubei of south east of Yunnan province; the III group included in 20 germplasm resources collected from the center of Yunnan province, north east of Yunnan province, Sichuan province, and Guizhou province. CONCLUSION: There were abundant genetic diversity in the germplasm resources of E. breviscapus, and the genetic relationships are closely related to geographical distance where they were collected.

[Study on optimal harvest time of Erigeron breviscapus].

OBJECTIVE: To ascertain the optimal harvest time of Erigeron breviscapus. METHOD: The dry matter weight accumulation of different organs in growth process and contents of scutellarin and coffeic acid ester in whole plant of E. breviscapus were determined. RESULT: The number of leaves per plant, the dried weight of single leaf and dry matter weight of whole plant and different organs reached the highest after seedling 130-140 d. The content of scutellarin gradually decreased with growth period, and sharply decreased after seedling 140 d. The content of coffeic acid ester varied irregularly with growth period. CONCLUSION: The optimal harvest time of E. breviscapus is in early bloom period after seedling 130 d.

[Determination of mineral elements in brown rice of near-isogenic lines population for Japonica rice by ICP-AES].

In the present paper, the contents of 17 mineral elements (S, Mo, Ni, Fe, Cr, Na, Al, Cu, P, Sn, Zn, B, Mn, Mg, Ca, Sr and K) in brown rice of 264 plant lines in near-isogenic lines (NILs) population and parents for Japonica rice were determined by ICP-AES technique. The method proved to be simple, rapid, highly sensitive and accurate, and can be used to determine many elements at the same time. Its recovery ratio obtained by standard addition method ranged between 92.3% and 110.27%, and its RSD was lower than 6%. The analytical results showed that NILs for various mineral elements based on the BC5F5 population consisting of 261 lines were developed from a cross between NIL (BC4F5) and Towada. To our knowledge, this is the first report on that near-isogenic lines NIL(BC4F5) with the important value for high mineral elements associated with cold tolerance at booting stage have been bred. The results of the determination show that the brown rice is rich in eleven elements such as P, K, Mg, S, Ca, Zn, Mn, Na, Fe, Cu and Al necessary to human health. There is smaller variation of 5 macroelements (11.15%-16.45%) but larger variation of 12 microelements (16.57%-94.96%) in brown rice from populations. There is significant correlation among 95 from 136 pairs in 17 elements, moreover, especially the correlation (0.531**-0.921**) among 15 pairs of six micro-elements (Mo, Ni, Al, Sn, Cr and Sr) associated with the active components of functional rice is relatively higher than that of 10 pairs (0.175**-0.867**) of 5 macroelements (P, K, Ca, Mg and S), revealing the importance of microelements to catalysing and synthesizing the active components of functional rice. The above results provided reliable data and theory bases for gene location and cloning of controlling elements contents in brown rice, and further revealed the molecular and physiological mechanism of the relation between mineral elements in brown rice and cold tolerance at booting stage in japonica rice from Yunnan Province of China.

[Rapid determination of transient expression characteristics of drought- and dehydration-inducible promoters from plants].

The selection of suitable inducible-promoters is one of the most important chains in transgenic researches for plant tolerances to drought, dehydration and other abiotic stresses. Based on laboratory researches in the past years, it was set up a set of methods that could be used to rapidly determine the transient expression characteristics of drought- and dehydration-inducible promoters by using whole barley seedling and plant leaves in vitro as bombardment objects. Promoters Dhn4s, Dhn8s, HVA1s, Rab16Bj and wsi18j isolated from barley and rice were able to express GFP in the leaves of barley, wheat, rice, sorghum and fern after drying treatment, but not in laves of mungbean and tomato. The qualitative expression of HVA1s and wsi18j in different organs and tissues of barley was identified. A method for quantitative analysis of promoter transient expression was established by means of GFP foci/GUS foci counting or GUS activity/XYN activity test. Finally, the value and prospect of the methodology were discussed in terms of its application to the analysis of plant promoters inducible by environmental factors.