Maize (Zea mays L.): A New Host for Ligustrum witches' Broom Phytoplasma.

Behçet Kemal Çağlar,Toufic Elbeaino,Ekrem Atakan,Serkan Pehlivan

doi:10.3390/pathogens10060723

Abstract

In the 2019–2020 growing season, two corn fields located in İmamoğlu town (Adana Province, Turkey) were surveyed following the appearance of phytoplasma-like symptoms on maize plants. A total of 40 samples were collected and tested in first-round and nested PCR using universal primer pairs P1/P7 and R16F2n/R16R2, respectively. All maize-diseased plants reacted positively, whilst no PCR amplifications were obtained from asymptomatic plants. Blast sequence analysis of R16F2n/R16R2-primed amplicons from different maize isolates showed 99.2% to 100% of identity with the 16S rRNA gene of Ligustrum witches’ broom phytoplasma (LiWBP). To gain additional molecular information on the 16S ribosomal RNA and 23S rRNA intergenic spacer region of LiWBP, not identified previously, the P1/P7-primed amplicons were also sequenced and analyzed. The results show that maize isolates from Turkey share 99.6% to 100% of identity among them, whereas the highest identity found (91%) was with members of groups 16SrII and 16SrXXV (peanut and tea witches’ broom groups, respectively). This distant relationship between LiWBP and members of 16SrII and XXV was also confirmed by RFLP and phylogenetic analyses. This is the first finding of LiWBP on maize in nature, where it was found responsible for phyllody disease of corn plants in Turkey. The additional molecular information acquired in this study on the 16S–23S rRNA intergenic spacer region of LiWBP further corroborates its distant relationship to any other phytoplasma groups.

Highlights

Maize (Zea mays L.) production occupies third place after wheat and barley in Turkey [1].According to the Turkish Statistical Institute, the estimated cereal output for 2020 is36.6 million tons, about 7% percent more than the average of the previous five years, including 20.5 million tons of wheat, 8.3 million tons of barley and 6 million tons of corn [1].Generally, maize is grown everywhere in the country, but the Çukurova region, known in the 1960s and 1970s as the cotton region, boasts of being the first-ranked cornproducing region in Turkey [2]
The additional molecular information acquired in this study on the 16S–23S rRNA intergenic spacer region of Ligustrum witches’ broom phytoplasma (LiWBP) further corroborates its distant relationship to any other phytoplasma groups
Liunique pathogen responsible for thefound symptoms observed on maize-affected plantsthat in the WBPvisited is a unique pathogen for the symptoms observed on(using maize-affected two fields

Summary

Introduction

Maize (Zea mays L.) production occupies third place after wheat and barley in Turkey [1].According to the Turkish Statistical Institute, the estimated cereal output for 2020 is36.6 million tons, about 7% percent more than the average of the previous five years, including 20.5 million tons of wheat, 8.3 million tons of barley and 6 million tons of corn [1].Generally, maize is grown everywhere in the country, but the Çukurova region, known in the 1960s and 1970s as the cotton region, boasts of being the first-ranked cornproducing region in Turkey [2]. Maize (Zea mays L.) production occupies third place after wheat and barley in Turkey [1]. In Turkey, phytoplasmas are considered among the most important pathogens that are limiting the agricultural production at the national level [4]. The recent discovery of many phytoplasma groups (16SrI, II, VI, IX, X and XII) on many crops such as tomato, cucumber, pepper, maize, peach, pear, pomegranates, eggplant, sesame and ornamentals, in different regions of the country [5,6,7,8,9,10,11,12,13], along with their insect vectors, has increased concern about the potential threat of these pathogens in the very short term to come.

Methods

Results

Conclusion