307 MAY 2017, VOL. 42 Nº 5 0378-1844/14/07/468-08 $ 3.00/0 Introduction An artificial seed coating is a layer that covers the entire seed surface. It is usually formed by inert materials to provide adequate handling, promote particular microenvi- ronments and protect seeds against pathogens and insect damage (Giménez-Sampaio et al. , 1992; Ziani et al., 2010; Zeng et al., 2012). Usually, seed coatings function as car- riers for pesticides which pro- tect the seeds and the emer- ging seedlings (Vavrina and McGovern, 1990; Kaufman, 1991). The coating agent should not be toxic or harm- ful for the plant or the envi- ronment. Chitosan is a natu- ral polymer that has shown good results when applied as seed coating for some crops (Benhamou et al. , 1994; Bhaskara Reddy et al., 1999; Boonlertnirun et al. , 2008; El Hadrami et al., 2010). This polymer is obtained from the deacetylation of chitin, the predominant component of arthropod exoskeletons and of cell walls of several fungi. Because it is biodegradable and non-toxic, and has anti- microbial properties, chitosan is seen as a versatile material for several agricultural appli- cations (Badawy and Rabea, 2011). It has been shown that chitosan elicits defense mech- anisms in plants through in- duction of glucanases, chiti- nases, phenolic compounds, terpenoids, PR proteins, prote- ase inhibitors, and compounds associated with oxidative burst, lignification and callose deposition (Bautista-Baños et al., 2006; Franco and Iriti, 2007; Mandal and Mitra, 2007; Hadwiger, 2013; Mejia- Teniente et al. , 2013). Chitosan has been used to coat corn, tomato, rice and wheat seeds and has been as- sociated with several effects that include better physiologi- cal quality, increased vigor, higher germination rates and induction of plant defenses (Benhamou et al. , 1994; Bhaskara Reddy et al., 1999; Boonlertnirun et al., 2008; Ziani et al. , 2010; Zeng et al. , 2012). This underlines the value of chitosan used as an additive for seed coating. The use of agrochemicals in com- bination with chitosan has been evaluated and has yield- ed good results (Kashyap et al., 2015; Symonds et al., 2016). However, compatibility of this polymer with benefi- cial microorganisms that are frequently incorporated in some seed coats remains to be explored in depth. Incorporation of beneficial agents into seed coatings has yielded good results in terms of plant protection, production or endophytic fungus coloniza- tion. The most common bene- ficial agents used for seed coating include Pseudomonas spp., Gliocladium spp., Glomus spp., Trichoderma spp. and Beauveria bassiana, which are associated with mineral solubi- lization, plant defense promo- tion, insect infection and an- tagonism on phytopathogens. Usually, these beneficial agents are mixed with adhesive com- ponents of polymeric nature, including xanthan gum, meth- ylcellulose, latex derivatives vulgaris L.) seeds by immersion. Neither coating treatment with chitosan affected seed germination. In the case of coating with fungicide, the shrimp chitosan allowed gradual release of the chemical agent on the seed surface for a longer time. Moreover, an important part of B. bassiana conidia incorporated into the coatings germinated, indicating that this type of biological agent can be used in coatings to provide seeds with biological protec- tion. Little germination of T. harzianum conidia was observed. More studies are needed to establish times and conditions to control germination of conidia in the coatings. SUMMARY Chitosan has been recommended for agricultural applica- tions as an adherent, additive or coating for seeds. It has also been reported to induce endogenous defenses and promote the establishment and development of seedlings. However, these properties seem to be associated to the evaluated species. In this paper, two kinds of chitosan coatings were generated and mixed with fungicide and with benefcial fungi conidia ( Beau- veria bassiana and Trichoderma harzianum). Chitosan from two sources (shrimp and insect Pterophylla beltrani) was used. Coat- ing mixtures were applied on the surface of bean ( Phaseolus CHITOSAN MIXED WITH BENEFICIAL FUNGAL CONIDIA OR FUNGICIDE FOR BEAN (Phaseolus vulgaris L.) SEED COATING Gilberto Ruiz-de-la-Cruz, César Leobardo Aguirre-Mancilla, Nancy Aracely Godínez-Garrido, Nely Monserrat Osornio-Flores and Jorge Ariel Torres-Castillo KEYWORDS / Beauveria bassiana / Biofunctional Coating / Germination / Trichoderma harzianum / Ziram® / Received: 31/10/2016. Modifed: 02/05/2017. Accepted: 04/05/2017. Gilberto Ruiz-de-la-Cruz. Ba- chelor in Biology, Instituto Tecnológico de México - Insti- tuto Tecnológico de Ciudad Victoria (ITN-ITVictoria), Mexico. Laboratory Assistant, Universidad Autónoma de Tamaulipas (UAT), México. e-mail: rc_grc@hotmail.com César Leobardo Aguirre-Man- cilla. Biochemical Engineer, Instituto Tecnológico de Coli- ma, México. M.Sc. and Doctor in Plant Biotechnology, CINVESTAV, Irapuato, Mexi- co. Professor Researcher, Instituto Tecnológico de Roque (ITN-ITR), Mexico. e-mail: ceaguirre@itroque.edu.mx Nancy Aracely Godínez-Garrido. Agroindustrial Engineer, Uni- versidad Autónoma Chapingo, M.Sc. in Seed Production and Technology, and doctoral stu- dent in Agroalimentary Pro- duction, ITN-ITR, Mexico. e-mail: nnancygg@hotmail.com Nely Monserrat Osornio-Flo- res. Food Industry Engineer and M.Sc. in Seed Production and Technology, ITN-ITR, Mexico. e-mail: nely_osorf@ live.com.mx Jorge Ariel Torres-Castillo. Ba- chelor in Biology, ITN-IT Vic- toria, Mexico. Doctor in Plant Biotechnology, CINVESTAV , Ira- puato, Mexico. Professor, UAT, Mexico. Address: Laboratorio de Biotecnología y Genética, Instituto de Ecología Aplicada, UAT. División del Golfo 356, Col. Libertad, 87019, Ciudad Victoria, Tamaulipas, México. e-mail: jor- gearieltorres@hotmail.com