Phylogenetic Diversity and Effect of Temperature on Pathogenicity of Colletotrichum lupini

Abstract

Although lupin anthracnose caused by Colletotrichum lupini is a significant threat for spring and winter lupin crops, it has been poorly studied so far. This study aimed at characterizing the (i) phylogenetic, (ii) morphological, and (iii) physiological diversity of collected isolates from anthracnose-affected lupins. The genetic identification of representative isolates (n = 71) revealed that they were all C. lupini species, further confirming that lupin anthracnose is caused by this species. However, multilocus sequencing on these isolates and 16 additional reference strains of C. lupini revealed a separation into two distinct genetic groups, both of them characterized by a very low genetic diversity. The diversity of morphological characteristics of a selected subset of C. lupini isolates was further evaluated. To the best of our knowledge, microsclerotia production observed for some isolates has never been reported so far within the Colletotrichum acutatum species complex. Finally, the modeling of growth responses of a subset of C. lupini strains revealed the capacity of some strains to grow in vitro at 5°C. This ability was also evidenced in planta, because C. lupini DNA was detectable in plants from 14 days postinoculation at 5°C onward, whereas symptoms began to appear a week later, although at a very low level. Since lupin crops are planted during winter or early spring, growth studies in vitro and in planta demonstrated the capability of the species to grow at temperatures ranging from 5 to 30°C, with an optimum close to 25°C. In this study, C. lupini-specific primers were also designed for real-time quantitative PCR on fungal DNA and allowed the detection of C. lupini in asymptomatic field samples. These results open perspectives to detect earlier and limit the development of this pathogen in lupin crops.

Deciphering the Infectious Process of Colletotrichum lupini in Lupin through Transcriptomic and Proteomic Analysis

“…C. lupini is a major threat for lupin crops and control solutions need to be found in order to use this leguminous crop in rotations as a promising alternative for protein sources. A few studies have been performed to identify its taxonomy through phylogenetic analysis [ 74 , 75 , 76 , 77 , 78 ], describe its morphology [ 75 , 77 , 78 ] and symptoms in the field [ 4 ] or evaluate the effect of temperature on its in vitro and in planta growth [ 78 , 79 , 80 ]. In this study, Illumina RNA sequencing and nLC mass spectrometry were used to identify candidate genes and proteins associated with C. lupini pathogenicity over the course of infection in lupin plants.…”

Development of PCR-based markers and whole-genome selection model for anthracnose resistance in white lupin (Lupinus albus L.)

“…Moreover, the Kiev Mutant × P27174 mapping population was phenotyped for resistance to anthracnose in Australia in wintertime, which is characterized by relatively low daily temperatures compared to those occurring in European regions where lupins are cultivated as a spring-sown crop. As the pathogenicity of C. lupini depends on the temperature pattern during infections and the strain of the pathogen (Dubrulle et al 2020 ; Thomas et al 2008 ), candidate lines selected by molecular markers should be subjected to disease resistance screening in local environment using domestic isolates.…”

Molecular Detection of the Seed-Borne Pathogen Colletotrichum lupini Targeting the Hyper-Variable IGS Region of the Ribosomal Cluster

“…Dubrulle et al (2019) used specific primers targeting a single copy gene to detect C. lupini DNA in winter and spring lupin fields in France. Of the 47 samples collected, C. lupini was quantified in six samples above the limit of quantification (LOQ) (10 −3 ng DNA), although all at a very low level (between 10 −3 and 5 × 10 −3 ng DNA) [24]. IGS region could be an attractive alternative to the ITS region when closely related taxa or even different species need to be investigated.…”

“…Due to this biological diversity, the C. acutatum species complex has been suggested as a suitable model to investigate genomic signatures associated with changes of key biological characters [4,23]. Recently, the intraspecific diversity of Colletotrichum associated with lupin crops in the western area of France and worldwide has been widely investigated [24]. All strains isolated from anthracnose-infected lupin have been identified as C. lupini , confirming that the disease is exclusively caused by this species.…”

“…All strains isolated from anthracnose-infected lupin have been identified as C. lupini , confirming that the disease is exclusively caused by this species. The genetic intraspecific diversity based on eight genomic loci with high resolution was low and revealed the presence of two distinct genetic groups [24].…”