**Pollen Allergenicity is Highly Dependent on the Plant Genetic Background: The "Variety"/"Cultivar" Issues**

Juan de Dios Alché, Adoración Zafra, Jose Carlos Jiménez-López, Sonia Morales, Antonio Jesús Castro, Fernando Florido and María Isabel Rodríguez-García

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/52815

#### **1. Introduction**

Type I hypersensibility to pollen is an important cause of allergy worldwide. In other types of allergy like the food allergic symptoms or very frequently the oral allergy syndrome (OAS), clear differences between varieties/cultivars of the same or highly-related plant species have been described as regard to the expression of allergens and their allergenic importance.

Pioneer studies were carried out in date palm tree over the later years of the last century (Kwaasi et al 1999, 2000). Such studies indicated that allergenicity to date fruit was a cultivar-specific phenomenon, and laboratory data showed that individual cultivars varied in their number of IgE immunoblot bands. Sera from fruit-allergic as well as pollen-allergic patients recognized common fruit-specific epitopes. Also, there was heterogeneity in patient responses to the different extracts. Nevertheless, a number of common allergens were responsible for cross-reactivity between the cultivars.

Up to date, similar studies have been carried out in an important number of plants, mainly those producing edible fruits like apple (Asero et al 2006; Rur 2007; Matthes and Schmitz-Eiberger 2009; Vlieg-Boerstra et al 2011), peach (Brenna et al 2004; Ahrazem et al 2007; Chen et al 2008), cherry (Verschuren, http://www.appliedscience.nl/doc/Onderzoek\_111117 \_Martie\_Verschuren.pdf), nectarine (Ahrazem et al 2007), tomato (Dölle et al 2011), strawberry (Muñoz et al 2010), and lichy (Hoppe et al 2006) among others, and in seeds like cereals (Nakamura et al 2005), buckwheat (Maruyama-Funatsuki et al 2004) and peanuts (Kang et al 2007; Kottapallia et al 2008).

© 2012 de Dios Alché et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 de Dios Alché et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Numerous analysis have raised the question that pollen grains, similarly to fruits may notably differ among different varieties/cultivars in terms of pollen micromorphology, as well as in their physiological characteristics (e.g. viability, vigour, ability to germinate, compatibility…) (Castro et al 2010; Ribeiro et al 2012), and eventually in their allergenic content. However, literature devoted to the comparison of the pollen allergenic characteristics intra- and inter- varieties is still relatively scarce. This article reviews most of these investigations.

Pollen Allergenicity is Highly Dependent on the Plant Genetic Background: The "Variety"/"Cultivar" Issues 3

(Radauer and Breteneder 2006). These authors managed to classify all pollen allergens known to date into a limited number of protein families, and divide them into ubiquitous (e.g. profilins), present in certain families (e.g. pectate lyases), or limited to a single taxon (e.g. thaumatin-like proteins). This approach provides invaluable help in issues like the prediction of cross-reactivity, the design of diagnostic methods and the assessment of the allergenic potential of novel molecules. A similar approach is described by Moreno-Aguilar (2008).

On the other hand, different authors are contributing to define the specific allergenic composition of pollens, going deeper into the taxonomical classification usually observed (this is, characterizing the allergenic composition of pollens at infraspecific level), and abounding into the analysis of pollen allergenic polymorphism. Advantages of such strategy have been

In botany, an infraspecific name is that corresponding to any taxon below the rank of species. Such names are constructed based in the use of trinomial nomenclature, regulated by the International Code of Botanical Nomenclature (ICBN) (McNeill et al 2006), which includes: genus name, specific epithet, connecting term indicating the rank (not part of the name, but required), and finally the infraspecific epithet. It is habitual to italicize all three parts of the name, but not the connecting term. Five different taxonomical ranks below the

A **subspecies** is a taxonomical rank formed by individuals of the same species which are capable of interbreeding and producing fertile offspring. However, they often do not interbreed in nature due to geographic isolation or other factors (http://en.wikipedia. org/wiki/Subspecies). The differences between subspecies are usually less distinct than the

A **botanical variety** is a taxonomic rank below that of species, characterized by differential appearance from other varieties. However, varieties retain the ability to hybridize freely among themselves, providing they become in contact. Usually, varieties are geographically separated. Varieties are named by using the binomial Latin name followed by the term

**Subvarieties, forms and subforms** constitute taxonomic ranks of "secondary" importance and are more rarely used. For example, a form usually designates a group with a noticeable but minor deviation. Some botanists believe that there is no need to name forms, since there are theoretically countless numbers of forms based on minor genetic differences

differences between species, but more distinct than the differences between varieties.

"variety" (usually abbreviated as "var.") and the name of the variety in italics.

outlined before (Alché et al 2007). Diverse examples of this strategy are depicted next.

a. subspecies - recommended abbreviation: subsp. ("ssp." also widely used)

**3. Infraspecific botanical names** 

species are explicitly allowed in the ICBN:

b. varietas (variety) - recommended abbreviation: var.

e. subforma (subform) - recommended abbreviation: subf.

d. forma (form) - recommended abbreviation: f.

(http://en.wikipedia.org/wiki/Form\_(botany)).

c. subvarietas (subvariety) - recommended abbreviation: subvar.
