AUTHOR=Della Lucia Maria C. , Bertoldo Giovanni , Broccanello Chiara , Maretto Laura , Ravi Samathmika , Marinello Francesco , Sartori Luigi , Marsilio Giovanni , Baglieri Andrea , Romano Alessandro , Colombo Mauro , Magro Francesco , Campagna Giovanni , Concheri Giuseppe , Squartini Andrea , Stevanato Piergiorgio 

TITLE=Novel Effects of Leonardite-Based Applications on Sugar Beet

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.646025

DOI=10.3389/fpls.2021.646025

ISSN=1664-462X

ABSTRACT=<p>The present study aimed to explore the effects of foliar application of a leonardite-based product on sugar beet (<italic>Beta vulgaris</italic> L.) plants grown in the field. The approach concerned the evaluation of the community compositional structure of plant endophytic bacteria through a metabarcoding approach, the expression level of a gene panel related to hormonal metabolism and signaling, and the main sugar beet productivity traits. Results indicated that plants treated with leonardite (dosage of 2,000 ml ha<sup>–1</sup>, dilution 1:125, 4 mg C l<sup>–1</sup>) compared with untreated ones had a significant increase (<italic>p</italic> &lt; 0.05) in (i) the abundance of <italic>Oxalicibacterium</italic> spp., recognized to be an endophyte bacterial genus with plant growth-promoting activity; (ii) the expression level of <italic>LAX2</italic> gene, coding for auxin transport proteins; and (iii) sugar yield. This study represents a step forward to advance our understanding of the changes induced by leonardite-based biostimulant in sugar beet.</p>