Plant Science xxx (2003) xxx–xxx Chlorogenic acid content swap during fruit maturation in Coffea pseudozanguebariae Qualitative comparison with leaves Claire Bertrand, Michel Noirot ∗ , Sylvie Doulbeau, Alexandre de Kochko, Serge Hamon, Claudine Campa Centre IRD of Montpellier, BP 64501, 34394 Montpellier Cedex 5, France Received 26 March 2003; received in revised form 22 July 2003; accepted 22 July 2003 Abstract Chlorogenic acids (CGA) are products of phenylpropanoid metabolism, i.e. one branch of the phenolic pathway. A wild species, Coffea pseudozanguebariae, native of East Africa, is a caffeine-free species with low CGA content (1.2% dmb in green beans). It is also used as a gene donor to improve C. canephora cup taste quality. In the current study, contents of the different CGA isomers were observed during the development in fruits and leaves. In both organs, CGA content decreased strongly during the growth and feruloylquinic acids (FQA) constituted most CGA. In fruits, a critical step was emphasised at the growth end, beyond which caffeoylquinic acid content (CQA) drastically increased. Previous results on beans suggest that the qualitative change concerned seeds and not pulp. The breeding implications and potential for further studies are discussed. © 2003 Elsevier Ireland Ltd. All rights reserved. Keywords: Coffea; Chlorogenic acids; Fruit maturation; Leaf development 1. Introduction CGA are products of phenylpropanoid metabolism, one branch of the phenolic pathway [1]. CGA sensu stricto (CGAs.s.) include only depsides of quinic acid with caffeic acid, i.e. caffeoylquinic acids (CQA) and dicaffeoylquinic acids (diCQA), but also, to a lesser extent, other hydrox- ycinnamoyl conjugates, such as ferulic or p-coumaric acid derivatives. In green coffee beans, 98% of CGA belong to three classes, i.e. CQA, diCQA and FQA (feruloylquinic acids) [2,3]. Each class includes three isomers according to the acylating residue positions [4] (Fig. 1). CGA are com- mon in many plants including Coffea species. Two coffee tree species are of worldwide importance: Coffea arabica and C. canephora (commonly known as Ro- busta), but C. arabica coffee—with its lower bitterness and better flavour—is preferred by consumers. Aroma and taste are produced during roasting as a result of Maillard and Stecker’s reactions and thermal degradation of precursors ∗ Corresponding author. E-mail address: noirot@mpl.ird.fr (M. Noirot). present in green beans [5]. This is how the chlorogenic acids (CGA) increase bitterness after their degradation into phenol derivatives [6]. The difference in CGA contents in C. ara- bica and C. canephora—4.1% dry matter basis (dmb) versus 11.3% dmb, respectively [7]—is a major element explain- ing flavour differences between these two coffees [4,8,9].A wild species, C. pseudozanguebariae, native of East Africa, has no caffeine and low CGA content (1.2% dmb) in green beans [10,11]. It can be used as a gene donor to improve C. canephora cup taste quality [11,12]. Evaluation and comparison of CGA contents in leaves and fruits during their growth are the first steps before analysing the expression of the genes controlling CGA biosynthesis, accumulation or degradation. From an organogenesis stand- point, leaves and fruits show some similarities, at least at youngest stages. Their differentiation over time, may be ac- companied by changes both in total CGA content and iso- mers proportions, due to tissue specific gene expression. To date, time-course variations of CGA contents have not been surveyed in leaves and fruits of Coffea species. To determine critical steps for CGA content variation in fruits have to be emphasised to understand modification of gene expression 0168-9452/$ – see front matter © 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.plantsci.2003.07.002