AUTHOR=Lekshmi R. S. , Sora S. , Anith K. N. , Soniya E. V. 

TITLE=Root colonization by the endophytic fungus Piriformospora indica shortens the juvenile phase of Piper nigrum L. by fine tuning the floral promotion pathways

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.954693

DOI=10.3389/fpls.2022.954693

ISSN=1664-462X

ABSTRACT=<p><italic>Piriformospora indica</italic>, the mutualistic biotrophic root colonizing endosymbiotic fungus belonging to the order Sebacinales, offers host plants various benefits and enhances its growth and performance. The effect of colonization of <italic>P. indica</italic> in <italic>Piper nigrum</italic> L. cv. Panniyur1 on growth advantages, floral induction and evocation was investigated. Growth and yield benefits are credited to the alteration in the phytohormone levels fine-tuned by plants in response to the fungal colonization and perpetuation. The remarkable upregulation in the phytohormone levels, as estimated by LC- MS/MS and quantified by qRT-PCR, revealed the effectual contribution by the endophyte. qRT-PCR results revealed a significant shift in the expression of putative flowering regulatory genes in the photoperiod induction pathway (<italic>FLOWERING LOCUS T, LEAFY, APETALA1, AGAMOUS, SUPPRESSOR OF CONSTANS 1, GIGANTEA, PHYTOCHROMEA</italic>, and <italic>CRYPTOCHROME1</italic>) gibberellin biosynthetic pathway genes (<italic>GIBBERELLIN 20-OXIDASE2, GIBBERELLIN 2-OXIDASE, DELLA</italic> PROTEIN <italic>REPRESSOR OF GA1-3 1</italic>) autonomous (<italic>FLOWERING LOCUS C, FLOWERING LOCUS VE, FLOWERING LOCUS CA</italic>), and age pathway (<italic>SQUAMOSA PROMOTER LIKE9, APETALA2</italic>). The endophytic colonization had no effect on vernalization (<italic>FLOWERING LOCUS C</italic>) or biotic stress pathways (<italic>SALICYLIC ACID INDUCTION DEFICIENT 2, WRKY family transcription factor 22</italic>). The data suggest that <italic>P. nigrum</italic> responds positively to <italic>P. indica</italic> colonization, affecting preponement in floral induction as well as evocation, and thereby shortening the juvenile phase of the crop.</p>