Fundação para a Ciência e a Tecnologia (FCT) - POCTI/AGR/40283/200

Conceição, Luís F. R.

Dias, Alberto Carlos Pires

Tavares, R. M.

Acta Physiologiae Plantarum

Universidade do Minho: RepositoriUM

Cell suspension cultures were faced with autoclaved CG biomass, for a period of 6 days, with or without prior treatment of suspension cells with salicylic acid (SA) or methyl jasmonate (MeJ). The effect of the SA and MeJ alone was also checked. Several culture samples were taken during the experimental period. Total lignin content was measured using a modified acetyl bromide assay (Fukushima and Dehority, 1995). Lignin production on both HP cell suspension varieties significantly changed in response to the elicitation procedures. The addition of MeJ (100 µM) lead to an increase on lignin accumulation (up to 100%), in the two HP cells lines, compared to the control. SA-treatment (25 µM) did not significantly affect lignin accumulation in both Hellos and HPS cultures. CG extract elicitation induced a significant decrease on lignin production (up to 50%) in HPS culture line (susceptible) but not in Hellos line (tolerant). Moreover, in MeJ-primed cells, post-treated with CG extract, 24h later, displayed lower amounts of lignin than cell cultures treated with MeJ only. Despite this fact, values were still 30 and 50% higher than those observed on control cultures of Hellos and HPS, respectively.In conclusion, production of lignin in HPS and Hellos cells is primed with MeJ-elicitation, a known inducer of plant defence responses against biotic stress. Interestingly, CG extract affected negatively to lignin production just in the susceptible-line culture (HPS). Figs. 1- 2: In vivo plants (1)  and cell suspension cultures (2) from H. perforatum  L.This work was supported by an FCT grant (POCTI/AGR/40283/2001).References: Fukushima RS, Dehority BA. 1995. Modificação do método colorimétrico “lignina solúvel em brometo de acetila” na estimativa quantitativa da lignina. Rev Soc Bras Zootec 24, 192-203.Hypericum perforatum (HP) is a very important medicinal plant. Efforts are made to improve the quality and consistence of supply of HP products, e.g. by employing selected HP accessions cultivated in the field instead of wild plant collections as raw material. Anthracnose caused by Colletotrichum gloeosporioides (CG) is a major problem in field cultivation of Hypericum perforatum. HP cell suspension cultures from two varieties, HPS (anthracnose-susceptible) and Hellos (anthracnose-tolerant), were utilized as tools for studying plant defence mechanisms against CG attack, namely changes in the lignin content. Changes in lignin content of Hypericum perforatum cells after Colletotrichum  gloeosporioides elicitationL.F. CONCEIÇÃO, R.M. TAVARES and  A.C.P. DIASCentro de Ciências do Ambiente, Department of BiologyUniversity of Minho, 4719-057 Braga, PortugalFig. 3: H. perforatum cell suspension cultures  (A) reated with MeJ or SA, prior to CG biomass addiction. (B) Treated with CG biomass onl: T y. (C) Control samples. (D) Treated with MeJ or SA, only.Fig. 4: Levels of lignin found on cell suspension cultures of H. perforatum HPS (A) and Hellos (B) during culture growth period.AB

Changes in lignin content of Hypericum perforatum cells after Colletotrichum gloeosporioides elicitation

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Universidade do Minho: RepositoriUM