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Context. Maize is a major crop in Italy and is constantly affected by the fungus Fusarium verticillioides, producing ear rot and grain contamination by fumonisins. Finding new genotypes resistant to Fusarium infection is an important goal for the improvement of maize cultivation. Aims. The objective of this work was to test a collection of 33 traditional landraces from the Emilia-Romagna (Italy) region for Fusarium ear rot (FER) severity, fumonisin content, and their agronomic performance. Methods. Primary ears were artificially inoculated with a toxigenic strain of F. verticillioides in a 2-year experimental trial. The landrace ‘Nostrano di Storo’ and a commercial hybrid of FAO maturity class 300 were also included and used as comparisons representing a well-known and highly valued landrace and a modern flint hybrid, respectively. Key results. The collection showed great phenotypic variability for all the agronomic traits assessed and responded differently to the Fusarium infection with percentages of FER ranging from 6.6% to 49.3%, and fumonisins from 4.3 mg/kg to 34.5 mg/kg. Thirteen and six landraces displayed FER percentages and fumonisin content very similar to the hybrid, respectively. Moreover, eight landraces exhibited grain yield values comparable to the hybrid. Interestingly, Va221, Va227 and EMR03 showed the best combination among these three traits. Conclusions. This local material can be considered suitable for breeding purposes targeting the development of FER and fumonisin resistant germplasm. Implications. The collection may represent a resource for future research aimed at evaluating the response to multiple pathogens and their associated mycotoxins.

The growing interest in maize landraces over the past two decades has led to the need to characterize the Italian maize germplasm. In Italy, hundreds of maize landraces have been developed, but only a few of them have been genetically characterized, and even fewer are currently employed in agriculture or for breeding purposes. In the present study, 13 maize landraces of the west Emilia-Romagna region were morphologically and genetically characterized. These accessions were sampled in 1954 from three provinces, Modena, Parma, and Piacenza, during the characterization project of Italian maize landraces. The morphological characterization of these 13 accessions was performed according to the UPOV protocol CPVO/TP2/3, examining 34 phenotypic traits. A total of 820 individuals were genotyped with 10 SSR markers. The genetic characterization revealed 74 different alleles, a FST mean value of 0.13, and a Nm mean of 1.73 over all loci. Moreover, AMOVA analysis disclosed a low degree of differentiation among accessions, with only 13% of genetic variability found between populations, supporting PCoA analysis results, where the first two coordinates explained only 16% of variability. Structure analysis, supported by PCoA, showed that only four accessions were clearly distinguished for both K = 4 and 6. Italian landraces can be useful resources to be employed in maize breeding programs for the development of new varieties, adapted to different environmental conditions, in order to increase crop resilience and expand the maize cultivation area.

Fusarium verticillioides (Fv) is a major cereal pathogen causing stalk rot and ear rot in maize, negatively affecting crop productivity and food safety. The maize WRKY transcription factors and the lipoxygenases (ZmLOXs) are well recognized as important players in plant defense against pathogens, and it is known that the host-pathogen lipid cross-talk influences the pathogenesis. In this regard, previous RNA-seq experiments reported the enhanced expression of ZmLOX genes in maize resistant genotypes and GWAS resulted in one SNP significantly associated with ZmWRKY125. The Clustered Regularly Interspaced Short Palindromic Repeat/associated Cas9 (CRISPR/Cas9) editing of ZmWRKY125 and the transgenic overexpression of ZmLOX4 genes were carried out to investigate the possible implication of these two genes in the resistance mechanisms against Fv. As regards ZmWRKY125, the CRISPR cloning was based on a double cloning using two different guides (sgRNA) for one gene target. Agrobacterium tumefaciens mediated transformation was used for introducing in Maize A188 line the construct under the maize promoter ZmpUBI in the binary vector p1609. Mutants from three different transformation events were obtained. For each event, T2 plants will be genotyped to find homozygous for the mutation that in turn will be phenotyped for Fv resistance and fumonisin content. As regards ZmLOX4, the gene was cloned under an overexpressed promoter involved in kernel development in the vector L1781, and the same transformation conditions adopted for the CRISPR/Cas9 editing of ZmWRKY125 were used. Mutants from two different transformation events were obtained. For each event, T2 plants were genotyped in order to find homozygous for the mutation. Homozygous plants will be further evaluated for Fv resistance, fumonisin accumulation, oxylipin content as well as for the expression analysis of the main genes involved in the jasmonic acid pathway.

Modern agriculture's greatest challenge lies in climate change, as the latter has significant impacts on agricultural systems through global warming, altered rainfall patterns, and increased frequency and intensity of extreme events. Maize, as a globally significant crop, is projected to be highly susceptible to climate change across Europe. To establish a more effective cropping system and develop resilient genotypes, existing market hybrids are inadequate due to their limited genetic diversity. In contrast, maize landraces - adapted to diverse agroecological conditions - can offer invaluable indigenous germplasm as a promising foundation for future genetic enhancements. The present research aims to achieve two objectives: a comprehensive study and genotyping of 28 Italian landraces, and the identification of genetic markers likely to be associated with environmental variables. Selected landraces from Lombardia, Emilia Romagna, Trentino-Alto Adige, Veneto, Toscana, Valle d’Aosta and Friuli Venezia Giulia were analysed using the GBS technique. Subsequent population studies were conducted based on the sequencing data, revealing 12 ancestral populations in the admixture analysis. Together with prominent and well-defined populations, including Nostrano Val Tidone, Châtillon and Entrebin, there are completely admixed groups comprising varieties from Trentino, Emilia Romagna, and Toscana, making it challenging to identify a singular reference population. The high degree of genetic fragmentation is reflected in the phylogenetic tree, which does not follow regional patterns but clearly distinguishes individual varieties. Notably, the Ottofile Mantovano variety stands out as the most distinct from all others, aligning with its unique field phenotype. In the PCA analysis as well, individual populations exhibit clear differentiation, although specific varietal groups are not discernible. Subsequently, a comprehensive analysis was conducted to investigate local adaptation in

While there is a rich collection of maize germplasm from Italy, it lacks genetic resources from the Aosta Valley, an isolated mountain region where landraces have been preserved in the absence of modern germplasm introductions. These local materials, which are still cultivated mainly at household level, can have high importance from a genetic and historical point of view. In the present study, five landraces named, after the collecting sites, Arnad, Arnad-Crest, Chatillon, Entrebin and Perloz, were sampled in Aosta Valley and subjected to historic, morphologic and genetic characterization. This study provided evidence for the landraces' long presence in Aosta Valley, a significant genetic variability and differentiation among the investigated landraces. Globally, 67 different alleles were detected ranging from 4 for markers phi127 and p-bnlg176 to 10 for phi031, with a mean of 6.7 alleles per locus. Observed heterozygosity levels were comprised from 0.16 to 0.51 and are generalkly lower than expected heterozigosity supporting fixation at some loci. STRUCTURE analysis revealed clear separation between accessions revealing the presence of four ancestral populations. This may be explained by the long reproductive isolation experienced by these materials. Finally, morphological observations confirm the high diversity between landraces revealing that they generally have flint kernels, variable color from yellow to dark red (Chatillon) while Perloz showed kernels with an apical beak. The present work confirms the importance of mountain areas in conserving biodiversity and increases the rich Italian maize germplasm with materials well adapted to marginal areas. Such new genetic variability may be used to breed new materials for more resilient agriculture.

Climate change poses a formidable challenge to modern agriculture, exerting notable effects on agricultural systems through global warming, altered rainfall patterns, and increased occurrence of extreme events. Maize, being a vital crop worldwide, is projected to face substantial vulnerability to climate change across Europe. Addressing this concern necessitates the development of a more resilient cropping system and the cultivation of genotypes that can withstand these challenges. However, current maize hybrids exhibit limited genetic diversity, making them inadequate for such endeavours. In contrast, maize landraces, which have adapted to various agroecological conditions, harbour valuable indigenous germplasm that holds promise for future genetic improvements. The primary objectives of this research are twofold: to conduct a comprehensive study and genotype analysis of 28 Italian landraces and to identify genetic markers associated with environmental factors. In the spring of 2022, carefully selected landracesfrom Lombardia, Emilia Romagna, Trentino-Alto Adige, Veneto, Toscana, Valle d’Aosta and Friuli Venezia Giulia were cultivated at the experimental farm of Università Cattolica del Sacro Cuore in Piacenza. Phenotypic characterization followed the UPOV protocol, with the apex of the final leaf sampled from five individuals per variety. Genotyping was performed using the GBS technique, and subsequent population studies based on sequencing data unveiled 12 ancestral populations in the admixture analysis. Noteworthy populations, including Nostrano Val Tidone, Châtillon, and Entrebin, displayed distinct and well-defined genetic profiles. Conversely, there were completely admixed groups consisting of varieties from Trentino, Emilia Romagna, and Tuscany, which posed challenges in identifying a singular reference population. The high degree of genetic fragmentation was evident in the phylogenetic tree structure, which did not conform to regional patterns but effecti

Despite the historical cultivation of maize (Zea mays L.) being well documented in Valle d’Aosta, no landrace from this mountain region was reported in the survey of maize carried out in 1949-1950. These materials are still cultivated and have high importance from a genetic and historical point of view. Recently, 5 landraces from Valle d’Aosta have been collected and subjected to historic, morphologic and genetic characterization. These landraces were named after the sampling location as it follows: Arnad, Arnad-Crest, Chatillon, Entrebin and Perloz. This study proved landraces’ long presence on Valle d’Aosta territory through information and photographs found in local archives. Moreover, the genetic characterization, which involved the use of SSR markers, highlighted a significant genetic variability and differentiation among the investigated landraces. This may be explained by the long reproductive isolation experienced by these materials. Finally, morphological observations confirm the high diversity between landraces revealing that they generally have flint kernels, variable colour from yellow to dark red (Chatillon) while Perloz showed kernels with an apical beak, suggesting the belonging to the “Rostrata” group. The present work confirms the importance of mountain areas in conserving agrobiodiversity and the richness of the Italian maize germplasm with materials well adapted to marginal areas. Such rich genetic variability may be characterized searching for useful traits for a more resilient agriculture.

The exploitation of heterosis is one of the leading activities in maize breeding. Here, we developed an innovative recombinant intercross (RIX) population by crossing pairs of multi-parental maize recombinant inbred lines (RILs) to evaluate the heterotic response in a heterozygous multi-parental population. Field phenotyping was performed on 400 RIX genotypes considering 11 agronomic traits and the resistance to Fusarium Ear Rot (FER) in two consecutive years. Thanks to the high level of allelic diversity available in parental genomes, a broad range of phenotypic diversity was observed. The broad-sense heritability (H2) was high for all traits (H2=0.48 to 0.89) illustrating a strong genetic basis. The heterotic response was computed based on RIL values as mid and best parent heterosis showing different magnitudes for different traits suggesting effects from partial dominance to over-dominance. GWAS detected 55 significant loci associated with agronomic traits across all chromosomes, with allelic effect ranging from 0.28 to 10.90 indicating the contribution of various sized QTLs. Several pleiotropic QTLs on chromosomes 8 and 3 were detected, indicating that these loci may contain valuable genes for multiple traits. RIX collection showed a moderate heritability of FER resistance and 7 putative QTL were associated to this trait on chromosomes 8 and 5. The allelic effect estimates indicated the presence of minor effect QTL with relatively small additive effects on disease resistance. Our findings confirm the usefulness of the RIX population to decipher heterotic loci in maize and support utilizing this resource in future to accelerate crop improvement.

The maize WRKY transcription factors and the lipoxygenases (ZmLOXs) are well recognized as important players in plant defense against pathogens. In this regard, previous RNA-seq experiments reported the enhanced expression of ZmLOX genes in maize resistant genotypes and GWAS resulted in one SNP significantly associated with ZmWRKY125. The Clustered Regularly Interspaced Short Palindromic Repeat/associated Cas9 (CRISPR/Cas9) editing of ZmWRKY125 and the transgenic overexpression of ZmLOX4 genes were carried out to investigate the possible implication of these two genes in the resistance mechanisms against F. verticillioides. As regards ZmWRKY125, the CRISPR cloning was based on a double cloning using two sgRNA for one gene target. Agrobacterium tumefaciens mediated transformation was used for introducing in maize A188 line the construct under the maize promoter ZmpUBI in the binary vector p1609. Mutants from three different transformation events were obtained. For each event, T2 plants will be genotyped to find homozygous for the mutation that in turn will be phenotyped for F. verticillioides resistance and fumonisin content. As regards ZmLOX4, the gene was cloned under a promoter involved in kernel development in the vector L1781, and the same transformation conditions adopted for the CRISPR/Cas9 editing of ZmWRKY125 were used. Mutants from two different transformation events were obtained. For each event, T2 plants were genotyped in order to find homozygous for the mutation. Homozygous plants will be further evaluated for F. verticillioides resistance, fumonisin accumulation, oxylipin content as well as for the expression analysis of the main genes involved in the jasmonic acid pathway.

Alternative strategies to control weeds are required at field level to reduce herbicides and derived pollution. Rye (Secale cereale L.) cultivation as cover crop is adopted mainly because of its allelopathic weed control, which takes place throughout a strong inhibition of germination and seedling growth in several grass and broad-leaved weeds. The present study consisted of: i) a field trial, focused on evaluation of biomass production and allelochemical concentration in the biomass, and in situ weed control at 30 days after termination (with two termination timings: T1 - heading phase and T2 - 10 days later) of 8 rye varieties; ii) a pot experiment, focused on the inhibition effect of mulches derived by those 8 rye varieties on four summer weeds: velvetleaf (Abutilon theophrasti Med.), lambsquarters (Chenopodium album L.), redroot pigweed (Amaranthus retroflexus L.), and common purslane (Portulaca oleracea L). Results showed that biomass production was the highest with Protector, closely followed by Primizia, Sito 70, Hellvus, Forestal, and Hymonta. In any case, rye mulching always reduced the weed biomass, especially with Fasto and Forestal. The allelochemical concentration in the biomass was the highest with Fasto and Forestal, and decreased on average from T1 to T2 (-38% for total BX and -57% for isovitexin). Conversely, the rye biomass production increased (on average + 77%) passing from T1 to T2. We found also that the reduction of weed biomass, compared with the control, is highly correlated with the allelochemical content in rye biomass in the case of T1 termination, while with the biomass production in the case of T2. In pots, a strong inhibitory effect on seedling growth due to rye mulching was observed for C. album (-76%), A. retroflexus (-56%), and P. olearcea (-84%), while not for A. theophrasti. We concluded that, whatever the variety, adopting rye as cover crop may be considered as a suitable practice to reduce weed pressure at the field level. Among

Food production is heavily dependent on soil phosphorus (P), a non-renewable mineral resource essential for plant growth and development. Alas, about 80% is unavailable for plant uptake. Arbuscular mycorrhizal fungi may promote soil P efficient use, although the mechanistic aspects are yet to be completely understood. In this study, plant and fungal variables involved in P acquisition were investigated in maize inbred lines, differing for mycorrhizal responsiveness and low-P tolerance, when inoculated with the symbiont Rhizoglomus irregulare (synonym Rhizophagus irregularis). The expression patterns of phosphate transporter (PT) genes in extraradical and intraradical mycelium (ERM/IRM) and in mycorrhizal and control maize roots were assessed, together with plant growth responses and ERM extent and structure. The diverse maize lines differed in plant and fungal accumulation patterns of PT transcripts, ERM phenotypic traits and plant performance. Mycorrhizal plants of the low-P tolerant maize line Mo17 displayed increased expression of roots and ERM PT genes, compared with the low-P susceptible line B73, which revealed larger ERM hyphal densities and interconnectedness. ERM structural traits showed significant correlations with plant/fungal expression levels of PT genes and mycorrhizal host benefit, suggesting that both structural and functional traits are differentially involved in the regulation of P foraging capacity in mycorrhizal networks.

Mycotoxin contamination of maize kernels by fungal pathogens Aspergillus flavus (Af) and Fusarium verticillioides (Fv) is a chronic global challenge impacting food security, health and trade. Current disease management practices are proven inadequate and strategies gearing towards hostmediated resistance can be an effective and sustainable approach to strengthen efforts to control the pathogens. Lipid modification into a diverse array of compounds, oxylipins, are recognized in response of plants to fungal pathogens. Lipoxygenase genes (LOXs) play a crucial role in the enzymatic oxidation of polyunsaturated fatty acids (PUFAs) into 9(S)- and 13(S)-hydroperoxides that are further metabolized into different oxylipins including jasmonates, oxo- and keto-fatty acids and volatiles. The involvement of maize LOXs (ZmLOXs) in this respect has been a subject of studies and their genetic manipulation resulted in the alteration of resistance or susceptibility to fungal pathogens in maize. However, the maize genome encodes six 9-LOX and seven 13-LOX isoforms and the specific role of each isoform remains elusive. The current study investigated the role of ZmLOXs in host resistance against the fungi Af and Fv using in silico and in planta approaches. The phylogenetic relationship, sequence similarity, protein domain structures, and transcript level structural variations were explored by comparing publicly available maize pan-genomes. Furthermore, the role of ZmLOXs against Af and Fv infection was investigated through their expression analysis along with further key genes involved in oxylipin biosynthesis, mycotoxin accumulation and lipid profiles in a ZmLOX4 mutant line (UFMulox4) together with W22, Mo17 and Tzi18 inbred lines at 3- and 7-days post-inoculation (dpi). ZmLOX proteins showed considerable variations in their sequences, functional domain structure and transcript structural variations among the pan-genome members. Among the studied lines, Tzi18 showed the highest resist

Italian maize germplasm is particularly rich in local materials and each region is characterized by the presence of peculiar local varieties deriving from centuries of adaptation, selection and cultivation. While the introduction of hybrids, during the 1950s, led to the disappearing of many of these varieties, some have been maintained in cultivation by farmers, frequently in marginal areas, as a kind of family heritage. Local varieties were identified throughout field surveys carried out in recent years. The discovery of a traditional popcorn variety over the most common flint and semi-flint materials used for production of polenta was interesting. Since these varieties have never been adequately described and reported in scientific literature, this study was aimed to solve this lack of knowledge on recently discovered local maize populations. Characterization represents the first step of a process focused on the preservation and possible exploitation of important genetic resources. Traditional materials are a useful reservoir of genes for adaptation to local conditions and climate changes. Adequate breeding programs can use such germplasm for developing new and more resilient varieties. These local materials have been characterized at the morphological level highlighting plant, ear and kernel differences. Genetic characterization, carried out on 455 individuals by the use of 10 SSR markers, revealed 62 different alleles ranging from four for markers phi127, phi076 and phi084 to nine for marker p-bnlg176. The landraces are well distinguishable at genetic level since 40% of genetic variability is present among accessions. Five landraces are characterized by the presence of private alleles and heterozygosity levels are generally good. These findings support the possibility to correctly preserve local materials through in situ conservation. Phylogenetic analysis evidenced the presence of varietal clusters, the clearest one formed by three red-pigmented accessions. STR

Nowadays, agriculture is under the pressure of climate change and new pathogen outbreaks while farmers are requiring breeders to develop more resistant and resilient genotypes. The genetic base for breeding may be increased through appropriate conservation, description and characterization of local varieties and germplasm collections that have never been used in breeding, and which could be sources of useful alleles. In this framework, the present paper focuses on eight maize landraces of the eastern part of Emilia-Romagna, derived from the Italian maize collection sampled in 1954. Landraces are characterized by a short cycle length and different kernel types—mainly flint-like or an intermediate type of yellow or yellow–orange color—while dent landraces are less represented. Pigmented and white corns are absent even though one landrace (Va213) showed the presence of scattered blue kernels on yellow ears. Ear shape is frequently conical, a trait associated with drought-resistance and common in Italian traditional landraces. Genetic characterization was carried out on 529 individuals by using 10 SSR markers. A total of 68 different alleles, ranging from 4 for markers (phi084 and umc1401) to 11 (phi031) and from 27 (Va217) to 50 (Va211), were evidenced at the individual and population level. AMOVA analysis revealed a small amount (19%) of variability between populations, as supported also by PCoA, with the only exception of Va217, which is different from the others, as evidenced also by phylogenetic analysis. Population structure analysis resulted in the identification of three and four population levels, which are consistent with previous results.

Mycotoxin contamination of maize kernels by fungal pathogens like Fusarium verticillioides and Aspergillus flavus is a chronic global challenge impacting food and feed security, health, and trade. Maize lipoxygenase genes (ZmLOXs) synthetize oxylipins that play defense roles and govern host-fungal interactions. The current study investigated the involvement of ZmLOXs in maize resistance against these two fungi. A considerable intraspecific genetic and transcript variability of the ZmLOX family was highlighted by in silico analysis comparing publicly available maize pan-genomes and pan-transcriptomes, respectively. Then, phenotyping and expression analysis of ZmLOX genes along with key genes involved in oxylipin biosynthesis were carried out in a maize mutant carrying a Mu transposon insertion in the ZmLOX4 gene (named UFMulox4) together with Tzi18, Mo17, and W22 inbred lines at 3- and 7-days post-inoculation with F. verticillioides and A. flavus. Tzi18 showed the highest resistance to the pathogens coupled with the lowest mycotoxin accumulation, while UFMulox4 was highly susceptible to both pathogens with the most elevated mycotoxin content. F. verticillioides inoculation determined a stronger induction of ZmLOXs and maize allene oxide synthase genes as compared to A. flavus. Additionally, oxylipin analysis revealed prevalent linoleic (18:2) peroxidation by 9-LOXs, the accumulation of 10-oxo-11-phytoenoic acid (10-OPEA), and triglyceride peroxidation only in F. verticillioides inoculated kernels of resistant genotypes.

Kernel size in cereal is an important agronomic trait controlled by the interaction of genetic and environmental factors. The endosperm occupies most of the kernel area; for this reason, the endosperm cells dimension, number and metabolic content strongly influence kernel properties. This paper presents the transcriptomic and metabolomic analysis of the maize defective endosperm 18 (de18) mutant, where auxin accumulation in the endosperm is impaired. This mutation, involving the ZmYuc1 gene, leads to a reduced kernel size compared to the wild-type line B37. Our results mainly indicate that IAA concentration controls sugar and protein metabolism during kernel differentiation and it is necessary for BETL formation. Furthermore, a fine tuning of different auxin conjugates is reported as the main mechanism to counteract the auxin deficit. Some candidates as master regulators of endosperm transcriptional regulation mediated by auxin are found between MYB and MADS-box gene families. A link between auxin and storage protein accumulation is highlighted, suggesting that IAA directly or indirectly, through CK or ABA, regulates the transcription of zein coding genes. This study represents a move forward with respect to the current knowledge about the role of auxin during maize endosperm differentiation thus revealing the genes that are modulated by auxin and that control agronomic traits as kernel size and metabolic composition.

Fusarium verticillioides infects maize, causing ear rot, yield loss and contamination by fumonisin mycotoxins. The fungus can be transmitted via kernels and cause systemic infection in maize. Maize resistance to the fungus may occur at different developmental stages, from seedling to maturity. Resistance during kernel germination is part of the plant-pathogen interaction and so far this aspect has not been investigated. In the present study, a genome wide association study (GWAS) of resistance to Fusarium during the seedling developmental stage was conducted in a maize diversity panel using 226,446 SNP markers. Seedling germination and disease phenotypes were scored on artificially inoculated kernels using the rolled towel assay. GWAS identified 164 SNPs significantly associated with the traits examined. Four SNPs were associated with disease severity score after inoculation, 153 were associated with severity in asymptomatic kernels and 7 with the difference between the severity ratings in inoculated and non-inoculated seeds. A set of genes containing or physically near the significant SNPs were identified as candidates for Fusarium resistance at the seedling stage. Functional analysis revealed that many of these genes are directly involved in plant defense against pathogens and stress responses, including transcription factors, chitinase, cytochrome P450, and ubiquitination proteins. In addition, 25 genes were found in high linkage disequilibrium with the associated SNPs identified by GWAS and four of them directly involved in disease resistance. These findings contribute to understanding the complex system of maize-F. verticillioides and may improve genomic selection for Fusarium resistance at the seedling stage.

Non presente

Beaked corn represents one of the most characteristics and neglected group of Italian maize landraces. These genotypes, classified in the “Rostrata” group, were mostly grown in northern Italy, on the left bank of the Pò river, until the end of the Second World War and then subjected to strong genetic erosion because of the subsequent introduction of improved genotypes and hybrids of US origin. These materials are experiencing a revival period for cultivation, commercial exploitation and an increased number of farmers is seeking particular genotypes for the production of niche products. In Valchiavenna (Sondrio, Lombardia, Italy) maize cultivation has historical importance for polenta preparation and is characterized by the presence of at least three accessions of “Mais Rostrato Val Chiavenna”, one conserved since 1982 in germplasm bank (here named as R17_BG) and two in situ (here named as R17_M; R17_T), with distinctive morphological traits at both ear and plant level. In the present study, these accessions have been characterized at the morphological and genetic level with 10 SSR markers and compared to other landraces of the Rostrata group. SSR analysis revealed from 3 to 11 alleles per locus evidencing a good level of heterosis and absence of allele fixation for landraces. Both phylogenetic and STRUCTURE analysis evidence that the three “Mais Rostrato Val Chiavenna” are different entities with a distinct genetic origin. Historical investigation revealed that the morphology most close to the “original” Mais Rostrato di Val Chiavenna is that of R17_T, dating back to the XIX century. These observations, coupled with morphological and genetic results may corroborate that R17_T corresponds to the original “Mais Rostrato Val Chiavenna”.

Biotic stresses are responsible for 20 to 40% losses of global agricultural productivity. Higher plants interact continuously with virus, fungi and bacteria, some of which lead to plant response firstly in the cell wall and cuticle acting as a physical barrier. However, successful resistance comes from a rapid switch on of the plant’s innate immune system, which involves the phytohormones salicylic acid (SA), jasmonic acid (JA) and ethylene (ET), main players in signal transduction. Strategies have been developed by pathogens to manipulate plant hormonal pathways and modify the immune signaling for their own resistance enhancement in the host. Nitric oxide (NO) participates in this challenging signaling pathway shared with reactive oxygen species during plant-pathogen interaction, playing a decisive role from both adversaries. The complex crosstalk between pathogen and plant will be discussed considering the main categories of pathogens and the genetic constitution of the host. Moreover, the phytohormones signaling and their network regulation along with the involvement of NO and reactive oxygen intermediates will be revised according the recent efforts in plant biotechnology. Now, a primary challenge is to identify and characterize the host genes underlying the proteins targeted by effector molecules and to design targets for future genome editing approaches. Among the New Breeding Techniques (NBT), the application of CRISPR/Cas9 editing has become an effective tool for future reinforcement of disease resistance in crops.

Fusarium verticillioides is one of the most relevant fungal species in maize responsible for ear, stalk and seedling rot, as well as the fumonisin contamination of kernels. Plant lipoxygenases (LOX) synthesize oxylipins that play a crucial role in the regulation of defense mechanisms against pathogens and influence the outcome of pathogenesis. To better uncover the role of these signaling molecules in maize resistance against F. verticillioides, the functional characterization of the 9‐LOX gene, ZmLOX4, was carried out in this study by employing mutants carrying Mu insertions in this gene (named as UFMulox4). In this regard, the genotyping of five UFMulox4 identified the mutant UFMu10924 as the only one having an insertion in the coding region of the gene. The impact of ZmLOX4 mutagenesis on kernel defense against F. verticillioides and fumonisin accumulation were investigated, resulting in an increased fungal susceptibility compared to the inbred lines W22 and Tzi18. Moreover, the expression of most of the genes involved in the LOX, jasmonic acid (JA) and green leaf volatiles (GLV) pathways, as well as LOX enzymatic activity, decreased or were unaffected by fungal inoculation in the mutant UFMu10924. These results confirm the strategic role of ZmLOX4 in controlling defense against F. verticillioides and its influence on the expression of several LOX, JA and GLV genes.

Il progetto RI.COL.MA (RIcupero, Caratterizzazione, COLtivazione del Mais Antico) è finanziato dal PSR 2014-2020 della Regione Emilia-Romagna. Obiettivo generale di RI.COL.MA è censire, recuperare, conservare e caratterizzare dal punto di vista morfologico, genetico, agronomico e tecnologico le varietà di mais tradizionali presenti in Emilia-Romagna, abbandonate da tempo dalle grandi colture e che rappresentano fonti di variabilità genetica per caratteristiche qualitative della granella e per adattamento all’ambiente. Le informazioni ottenute saranno rese disponibili attraverso attività di disseminazione e formazione che permetteranno alle aziende che intendono utilizzare le varietà tradizionali di mais di sviluppare nuove filiere produttive e, nello stesso tempo, di conservare il patrimonio storico e culturale alla base della biodiversità maidicola. Il progetto vede coinvolte l’Università Cattolica del Sacro Cuore di Piacenza, l’Università degli Studi di Pavia, il CRPV (Centro Ricerche Produzioni Vegetali) e otto aziende agricole emiliano-romagnole.