AUTHOR=Gabriel Márcia , Santos Marcilene F. A. , Mattos Vanessa S. , Gomes Ana Cristina M. M. , de Almeida Sheila F. , Castagnone-Sereno Philippe , Boiteux Leonardo S. , Cares Juvenil E. , Carneiro Regina M. D. G. 

TITLE=Comparative histopathology of virulent and avirulent Meloidogyne javanica populations on susceptible and resistant tomato plants

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1425336

DOI=10.3389/fpls.2024.1425336

ISSN=1664-462X

ABSTRACT=<p>The <italic>Mi-</italic>1.2 gene confers resistance to a wide range of <italic>Meloidogyne</italic> species, being the most important resistance factor employed in tomato breeding so far. However, many aspects related to the interaction of <italic>Mi-</italic>1.2-carrying tomato cultivars and virulent/avirulent <italic>Meloidogyne</italic> populations have not yet been clarified. Herein, comparative histopathological analyses were carried after inoculation of the homozygous (<italic>Mi</italic>-1.2/<italic>Mi</italic>-1.2) tomato rootstock ‘Guardião’ and the susceptible cultivar ‘Santa Clara’ (<italic>mi</italic>-1.2/<italic>mi</italic>-1.2) with virulent and avirulent populations of <italic>M. javanica.</italic> In the susceptible control, it was possible to visualize second stage juveniles (J2) of avirulent population and feeding sites from 2 to 30 days after infection (DAI) with females reaching maturity at 24-34 DAI. In the resistant rootstock, the <italic>Mi-</italic>1.2 gene-mediated resistance was related mainly to early defense responses (pre-infection and hypersensitive reaction), which led to an immunity-like phenotype that completely prevented the reproduction of the avirulent <italic>Meloidogyne</italic> population. On the other hand, J2s of the virulent <italic>M. javanica</italic> population were able to penetrate roots much more than the avirulent population, migrated and developed normally, showing intense and similar pattern of penetration from 4 to 34 DAI in the root tissues of both resistant and susceptible tomato genotypes. The total numbers of J2, J3, J4, and females counted in ‘Santa Clara’ for the virulent population of <italic>M. javanica</italic> were higher than in ‘Guardião’.</p>