A Blind-Identification Test on Criconema annuliferum (de Man, 1921) Micoletzky, 1925 Species Complex Corroborate the Hyper-Cryptic Species Diversity Using Integrative Taxonomy

Antonio Archidona-Yuste; Juan Emilio Palomares-Rius; Ilenia Clavero-Camacho; Carolina Cantalapiedra-Navarrete; Gracia Liébanas; Pablo Castillo

doi:10.3390/plants12051044

A Blind-Identification Test on Criconema annuliferum (de Man, 1921) Micoletzky, 1925 Species Complex Corroborate the Hyper-Cryptic Species Diversity Using Integrative Taxonomy

Plants (Basel). 2023 Feb 24;12(5):1044. doi: 10.3390/plants12051044.

Authors

Antonio Archidona-Yuste¹, Juan Emilio Palomares-Rius¹, Ilenia Clavero-Camacho¹, Carolina Cantalapiedra-Navarrete¹, Gracia Liébanas², Pablo Castillo¹

Affiliations

¹ Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Avenida Menéndez Pidal s/n, Campus de Excelencia Internacional Agroalimentario, ceiA3, 14004 Córdoba, Spain.
² Department of Animal Biology, Plant Biology and Ecology, University of Jaén, Campus 'Las Lagunillas' s/n, Edificio B3, 23071 Jaén, Spain.

Abstract

Ring nematodes are obligate ectoparasites on crops and natural herbaceous and woody plants, and some species are of economic importance and cause damage to roots of several crops. Recent integrative taxonomical analyses recognized the existence of two cryptic species within the Criconema annuliferum morphotype in Spain. In this study, we corroborated that morphometric, morphological and a multi-locus analysis (including the ribosomal markers D2-D3 expansion segments of 28S rRNA, ITS rRNA, 18S RNA, and the mitochondrial DNA cytochrome oxidase I gene) identified a new lineage clearly separated from C. annuliferum, C. paraannuliferum and C. plesioannuliferum. The new lineage was described herein as Criconema pseudoannuliferum sp. nov., confirming that C. annuliferum species complex species complex comprises a hyper-cryptic species complex. This research analysed soil samples from the rhizosphere of maritime pine (Pinus pinaster Ait.) forests in Bermeja-Crestellina Mountain, located at the western part of Málaga province, southern Spain. The integrative taxonomical analyses revealed the occurrence of a new cryptic species identified using females, males and juveniles with detailed morphology, morphometry and molecular markers, described herein as Criconema pseudoannuliferum sp. nov. All molecular markers (D2-D3, ITS, 18S and COI) were obtained from the same individual that was also used for morphological and morphometric analyses. This research demonstrated the hidden diversity within the C. annuliferum species complex species complex can reach to four lineages under ribosomal and mitochondrial gene markers for one morphospecies group, which includes four species, viz. C. annuliferum, C. paraannuliferum, C. plesioannuliferum, and C. pseudoannuliferum sp. nov. Criconema pseudoannuliferum sp. nov. was detected in moderate soil density in two maritime pine forests (5 and 25 nematodes/500 cm³ of soil) suggesting that does not cause damage to maritime pine.

Keywords: D2-D3 expansion domains of the large ribosomal subunit (28S); cytochrome c oxidase subunit 1 (COI); haplotype; internal transcribed spacer (ITS); multivariate morphometric analysis; species separation.

Grants and funding

This research was supported by the Spanish Ministry of Science, Innovation and Universities, grant number RTI2018-095345-B-C21, LITHOFOR (“Modulating role of LITHOlogy in the response of Mediterranean FORest ecosystems to climate change: growth, edaphological processes and future predictions”); and grant RYC2021-031108-I, funded by MCIN/AEI/10.13039/501100011033 and UE “Next Generation EU/PRTR”.