Molecular marker associated with a deleterious recessive anomaly in Eucalyptus grandis seedlings

Abstract

International audienceAbstract Key messageThe identification of an anomaly with deleterious effect and Mendelian segregation (3 normal: 1 abnormal) allowed the detection of a marker linked to a locus for the anomalous phenotype. This marker could be useful in marker-assisted breeding programs and for understanding this anomaly. ContextDue to the mixed mating systems in Eucalyptus genera, outcrossing populations exhibit low inbreeding depression (abnormalities). In this study, we identified a developmental anomaly in a controlled cross of Eucalyptus grandis, with Mendelian segregation. The anomaly was characterized by branching, reduced height, smaller individual leaf area, and asymmetrical leaf shape. Aims and methodsTo investigate and evaluate the anomaly detected, we performed morphological and molecular analysis. The genitors and bulks of normal and abnormal individuals were screened with random primers. The polymorphic markers that co-segregated with the anomalous phenotype were selected, validated, converted into SCAR markers and analyzed in silico. ResultsMorphological analysis showed significant differences between normal and abnormal phenotypes. The co-segregating marker was present in one genitor, in all abnormal individuals, and in 31 % of normal individuals (recombinants). In silico analyses revealed a mutation of two base pairs between the contrasting phenotypes and identified the marker in an intergenic region presenting partial identity with an expressed sequence tag (EST) of Bet v1-like genes. ConclusionA marker was developed to identify the recessive allele for the anomaly in E. grandis. This will be important for management of crosses in eucalypt breeding programs and in anomaly studies

Defense response-like reaction associated with an anomaly in Eucalyptus grandis

“…In a full-sib offspring from a controlled cross of Eucalyptus grandis performed at Suzano Papel and Celulose SA company, we observed an anomaly with a Mendelian segregation ratio of 3 normal: 1 abnormal seedling, indicating deleterious recessive alleles in homozygosis as the cause of the anomaly, as described in a previous study (Fuchs et al 2015). Our previous work showed that the abnormal seedlings died within a few months and presented some peculiar characteristics, including branching, reduced height, reduced individual leaf area, and leaf shape modifications.…”

“…Our previous work showed that the abnormal seedlings died within a few months and presented some peculiar characteristics, including branching, reduced height, reduced individual leaf area, and leaf shape modifications. We subsequently repeated the crossings to confirm the results obtained in Fuchs et al (2015) and included a Sequence Characterized Amplified Region (SCAR), a PCR-based marker associated with these morphological effects. In the present study, we evaluated plants at 4 months of age, a period at which the symptoms are more evident, enabling us to correctly distinguish phenotypes.…”

“…Leaf, stem, and root tissue of normal and abnormal seedlings were harvested 4 months after germination, frozen in liquid nitrogen, and stored at − 80 °C until nucleic acid extraction. The phenotypes under study were described in Fuchs et al (2015), where abnormal plants presented reduced growth, leaf malformation, shoot branching, and reduced root volume, in addition to mortality after 4 months.…”

Quantity, organization, and distribution of chloroplast microsatellites in all species of Eucalyptus with available plastome sequence

“…The development of molecular markers for Eucalyptus species improved dramatically after the complete sequencing of its nuclear genome (nDNA) (Myburg et al 2014, Fuchs et al 2015. Currently, microsatellite markers (SSRs) are widely used in.…”

Rust resistance and mating system in Eucalyptus grandis Hill ex Maiden progenies

“…Plant breeding programs have used molecular markers, directly and indirectly, to assist breeders in selecting genes of agricultural or forestry interest, by characterizing and identifying clones (parental and phylogeny tests), as well as planning crosses (FUCHS et al, 2015;VAILLANCOURT et al, 1998). BRONDANI et al (1998) listed a few comparative advantages of these genetic markers regarding co-dominance inheritance, such as multiallelism.…”