Powdery mildew caused by Erysiphe pisi DC is an important pea disease which causes high yield and quality losses. The most efficient way to control this disease is the use of resistant cultivars. Three genes of resistance are known so far in pea, namely er1, er2 and Er3. The most widely deployed gene in pea cultivars worldwide is er1. Resistance conferred by er1 is complete and considered to be durable, being recently demonstrated that er1 is in fact a member of the mlo gene family. Resistance is caused by colony abortion albeit the responsible cellular mechanisms causing this colony abortion are not known. In this study, the presence of different mechanisms related with colony abortion, such as callose apposition, protein cross-linking and hypersensitive response was quantified in a resistant pea er1 line compared to a susceptible check. Our histological studies showed that protein cross-linking, plays a determinant role in the penetration resistance conferred by er1, whereas callose apposition or hypersensitive response played little role.

Quantitative trait loci associated to drought tolerance in pea (Pisum sativum L.).

Mediterranean environments are of most interest to study pea adaptability to terminal drought conditions especially in the current context of global climate change. In our work we have tested 9 pea cultivars in five South European and North African locations, characterized by different agro climatic conditions within the Mediterranean climate. Data were processed through the additive main effects and multiplicative interaction (AMMI) analysis. Grain yield, aboveground biomass and flowering date were assessed within each Mega Environment (ME) with parametric and non-parametric methods, establishing ranks for the genotypes within each condition attending to their stability parameters and mean values. The field analysis revealed HR1 as a wide adapted genotype, whereas others such as Desso showed the best adaptation in South Mediterranean areas. Our results also highlighted the potential interest of these genotypes and others (i.e. Messire and ZP108) in breeding programs and further studies on drought tolerance.Additional Keywords: dry pea, phenology, Genotype × Environment interaction, drought tolerance Pea behaviour in Mediterranean field environments 5 IntroductionDry pea (Pisum sativum L.) is the most widely grown temperate grain legume in Europe and the second-most in the world (FAOSTAT 2013), being a versatile and inexpensive protein source for animal feeding with a widely acknowledged beneficial role in cropping systems (Drinkwater et al., 1998; Badgley et al., 2006;Nemecek et al. 2008). In spite of these advantages, dry pea acreage shows a constantly decreasing trend at a world level from 10.3 million ha in 1962 to 6.3 ha in 2012 (Rubiales and Mikic 2015).Yield variability and instability are the major problems for pea both within and between sites and seasons due to a poor adaptability and a low tolerance to biotic and abiotic stress (Moot et al. 1995;Jacobsen et al. 2012). Significant efforts have been made in pea breeding for adaptability to continental and oceanic conditions (Cousin 1997). In contrast, little efforts have been paid to improve adaptability to Mediterranean environments with mild winters and dry springs, where spring pea types are autumn sown and challenged by different stresses (Rubiales et al. 2009). As a result, pea cultivation is particularly low in the Mediterranean Basin and recently released pea cultivars are poorly adapted to Mediterranean environments (Rubiales 2015). This is somehow surprising as the East Mediterranean and the West Asia are the primary centre of diversity for pea, where wild forms, such as P. fulvum Sm. and P. sativum subsp. elatius (M. Bieb.) Asch. and Graebn can still be found growing today (Rubiales et al. 2011; and where pea once played a very important role in human diets, as witnessed by the first attested ancient DNA extraction from any legume species Medović et al. 2011).In field conditions, the development of pea genotypes producing high and stable seed yield is most decisive (Cousin, 1997;Rubiales et al. 2011;Smýkal et al. 2012), albeit high...

Abiotic stresses caused by adverse environmental conditions are responsible for heavy economic losses on pea crop, being drought one of the most important abiotic constraints. Development of pea cultivars well adapted to dry conditions has been one of the major tasks in breeding programs. The increasing food requirements drive the necessity to broaden the molecular basis of tolerance to drought to develop pea cultivars well adapted to dry conditions. We have used a shotgun proteomic approach (nLC-MSMS) to study the tolerance to drought in three pea genotypes that were selected based on differences in the level of water deficit tolerance. Multivariate statistical analysis of data unraveled 367 significant differences of 700 identified when genotypes and/or treatment were compared. More than half of the significantly changed proteins belong to primary metabolism and protein regulation categories. We propose different mechanisms to cope drought in the genotypes studied. Maintenance of the primary metabolism and protein protection seems a strategy for drought tolerance. On the other hand susceptibility might be related to maintenance of the homeostatic equilibrium, a very energy consuming process. Data are available via ProteomeXchange with identifier PXD004587.