Abstract
Rice bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) implies substantial yield loss to rice. In times of climate change, increasing temperatures are observed and further acceleration is expected worldwide. Increasing temperature often turns into inhibition of host plant defense to pathogens. Recently, a reduced resistance in rice IRBB4 carrying Xa4, but an increase in resistance in IRBB7 carrying Xa7 resistance by increasing temperature has been reported. Influence of high temperature on both R genes (Xa4+Xa7) combined in IRBB67 was analyzed under growth chamber conditions and transcriptomic analysis performed. The pyramided line IRBB67 showed no differences in lesion length between both temperature regimes, demonstrating that non-effectiveness of Xa4 at high temperature did not affect IRBB67 resistance. Moreover, Xa4 complements Xa7 resistance with no Xoo spread in planta beyond the symptomatic area under both temperature regimes in IRBB67. Time course transcriptomic analysis revealed that temperature enhanced IRBB67 resistance to combined heat and Xoo. Our findings highlight altered cellular compartments and point at a role of the cell wall involved in Xoo resistance and heat stress tolerance in both susceptible (IR24) and the resistant (IRBB67) NILs. Interestingly, up-regulation of trehalose-6-phosphatase gene and low affinity cation transporter in IRBB67 suggest that IRBB67 maintained a certain homeostasis under high temperature which may have enhanced its resistance. The interplay of both heat stress and Xoo responses as determined by up-regulated and down-regulated genes demonstrates how resistant plants cope with combined biotic and abiotic stresses.
Highlights
The world population is projected to reach 9.7 billion by 2050 and half the world population growth is expected in developing countries[1]
The highest plant height under low temperature was recorded on IRBB7 and under high temperature on IRBB4 (Fig. 1B)
Xa7 resistance mechanisms may confer an abiotic tolerance component which enhances its reaction to Xanthomonas oryzae pv. oryzae (Xoo) under temperature rise, Xa4 resistance mechanism may not be affected by temperature when it is combined with Xa7 in IRBB67
Summary
The world population is projected to reach 9.7 billion by 2050 and half the world population growth is expected in developing countries[1]. Oryzae (Xoo) interaction, Webb et al.[19] reported high temperature reducing the resistance of rice IRBB NILs carrying the Xa4 resistance gene to Xoo. Studying the effect of high temperature on the rice Xanthomonas oryzae pv. Oryzae (Xoo) interaction, Webb et al.[19] reported high temperature reducing the resistance of rice IRBB NILs carrying the Xa4 resistance gene to Xoo According to these authors, an inverse response was observed in IRBB7, a NIL with Xa7 resistance gene. A recent study revealed that pyramided line IRBB61 carrying three R-genes (Xa4, xa[5] and Xa7) showed more resistance to the combined high temperature and Xoo stress[21]. Combinations pathogen infection with high temperature or with drought stress alter gene expression by activation of specific programs, revealing that plant response to multiple stresses differs between reactions to one or more stresses[26]. Understanding how resistant plants respond to Xoo and heat stress will provide information to be used for developing double stress tolerant rice varieties
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
