Seed Science Research 13: 139-153 (2003)

Distinct expression patterns of ß-1,3-glucanases and chitinases during the germination of Solanaceous seeds

Luciana Petruzzelli (1), Kerstin Müller (2), Katrin Hermann (2), Gerhard Leubner-Metzger (2)

(1) Istituto Biosintesi Vegetali, C.N.R., via Bassini 15, I-20133 Milano, Italy
(2) Institut für Biologie II, Botanik, Albert-Ludwigs-Universität, Schänzlestr. 1, D-79104 Freiburg i. Br., Germany

Received: 10 July 2002 / Accepted after revision: 8 January 2003

Abstract. The expression patterns of ß-1,3-glucanases (ßGlu) and chitinases (Chn) were investigated during the seed germination of type members of the Cestroideae (three Nicotiana species, Petunia hybrida) and the Solanoideae (Capsicum annuum, Physalis peruviana) subgroup of Solanaceous species. Rupture of the micropylar testa (seed coat) and rupture of the micropylar endosperm, i.e. radicle emergence, were distinct and temporally separate events during the germination of Cestroideae-type seeds. ßGlu accumulation in imbibed Cestroideae-type seeds occurred after testa rupture, but prior to endosperm rupture, was inhibited by abscisic acid (ABA) and promoted by gibberellins (GA) and light in strict association with germination, and appeared to be caused by transcriptional regulation of the class I ßGlu genes. The micropylar cap of Solanoideae-type seeds does not allow a distinction between testa and endosperm rupture, but ßGlu accumulation occurred prior to radicle emergence of pepper and P. peruviana seeds. ABA inhibited endosperm rupture and ßGlu accumulation in the micropylar cap of pepper seeds. In contrast to tomato, ßGlu accumulation in pepper seeds was not only confined to the micropylar cap, was due to distinct, tissue-specific ßGlu isoforms, and was not accompanied by Chn accumulation. In conclusion, ABA inhibition of germination and ßGlu accumulation in the micropylar endosperm appears to be a widespread event during the seed germination of Solanaceous species. In contrast, accumulation of Chn and of distinct ßGlu isoforms in the embryo prior to germination appears to be a species-specific phenomenon within the Solanaceae. In addition, a post-germination co-induction of ßGlu and Chn in the root of the emerged seedling was found in endospermic and non-endospermic species and could represent an evolutionary conserved event during dicot seedling development.

Key words: abscisic acid - Capsicum - chitinase - gibberellin - ß-1,3-glucanase - Nicotiana - seed germination - Solanaceae family

Article in PDF format (780 KB)
Abstract               Fig. 1          Fig. 2          Fig. 3          Fig. 4     
                            Table 1          Table 2          Table 3
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