In the race against environmental stressors that threaten agricultural productivity and nutritional security, the world’s food crops face a continuous battle for survival and optimal development. Among these crops, maize (Zea mays L.) stands as a staple food source, integral to countless diets across the globe. However, its vulnerability to low temperature stress during critical growth phases, like seedling development, can drastically hamper yield and quality.
A landmark study led by Xiang Nan N from the School of Food Science and Engineering at South China University of Technology in Guangzhou, China, in collaboration with international experts, presents an innovative approach to shield maize seedlings from this chilling menace and to bolster their nutritional content, particularly the carotenoids–– vital compounds for both plant health and human nutrition.
Published under exclusive license by Springer-Verlag GmbH Germany, part of Springer Nature, their findings reveal a robust strategy involving the application of the plant hormone abscisic acid (ABA) to modulate carotenoid biosynthesis, effectively countering low temperature-induced nutrient decline in maize.
Low temperature often impedes carotenoid accumulation in maize seedlings. These biological pigments are not only essential for plant resistance against chilling but are also powerful antioxidants linked with various health benefits in humans, including the prevention of chronic diseases and the maintenance of eye health.
The comprehensive study entitled “Modulation of carotenoid biosynthesis in maize (Zea mays L.) seedlings by exogenous abscisic acid and salicylic acid under low temperature,” delves into the bioactive functions of carotenoids and explores external applications of ABA and salicylic acid (SA) as potential agents for mitigating low temperature stress in maize seedlings.
Through scrupulous quantitative analysis, the research team discovered that low temperatures led to a stark reduction in carotenoid levels, retaining only 62.8% compared to unstressed control seedlings. The application of ABA shone as a beacon of hope as it steered the expression of key structural genes including PSY3, ZDS, and CHYB, by interacting with ABA-responsive cis-acting elements (ABREs) in their promoter regions. A striking increase in the total carotenoid concentration to 1121 ± 47 ng·g^-1 fresh weight (FW) confirmed ABA’s potential in alleviating chilling stress by enhancing the nutritional profile of the maize seedlings.
On the other hand, SA, despite its recognized role in plant physiology, notably only the neoxanthin content witnessed a significant boost to 52.12 ± 0.45 ng·g^-1 FW by SA treatment, suggesting a more targeted avenue for biofortification of specific nutrients.
The relationship between the structural genes and carotenoid synthesis emerged as a critical piece of the puzzle. The research presented strong correlations of PSY1 with β-carotene and zeaxanthin (r = 0.93 and 0.89), while CRTISO exhibited ties with total carotenoids (r = 0.92), illuminating their pivotal roles in the overall accumulation of carotenoids.
These groundbreaking results underscore the nuanced mechanisms through which ABA could act as a reinforcement against chilling stress, enhancing the likelihood of a bumper crop rich in key nutrients. The use of ABA stands not only as a protective measure but also as an opportunity for agricultural innovation, offering farmers and the agrifood industry a tool to ensure the resilience and healthfulness of one of the world’s most consumed cereals.
Moreover, the implications of such a study extend to the domain of food security and nutrition. Considering the annual impact of chilling temperatures on crop yields and the subsequent strain on food supply chains, harnessing the power of ABA could significantly contribute to stable food production amid climatic challenges. This has a ripple effect on global nutrition, particularly in regions that rely heavily on maize as a dietary staple.
The diverse expertise of the research team, representing institutions such as the Guangdong Academy of Agricultural Sciences in China, and the University of British Columbia in Canada, exemplifies the importance of multidisciplinary collaboration in addressing global food challenges. The study integrates molecular genetics, plant physiology, and food science to provide a holistic understanding of how plant-based food sources can overcome environmental constraints while improving the nutritional yield for human consumption.
Going forward, the findings from this study pave a solid path for additional research. Future projects may focus on long-term field trials to evaluate the practical implications of ABA application on crop performance in varying climates. Coupled with advancements in genetic engineering and selective breeding, the insights gained from this work might contribute to the development of maize varieties inherently stronger against chilling stress and rich in essential nutrients.
Furthermore, the nuanced understanding of the carotenoid biosynthesis pathway unlocked by this research holds promise for its application in a broader spectrum of crops, potentially offering similar protective and nutritional enhancements. This could be a game-changer for regions prone to cold stress and may significantly expand the repertoire of strategies available for boosting the resilience of global food systems.
In essence, the modulation of carotenoid biosynthesis via ABA application is a beacon of innovation in crop management, marrying the interests of agricultural productivity, food nutrition, and human health. It’s a testament to the power of science in reinforcing the foundations of our food supply and rising to the challenges imposed by an ever-changing climate. As the team of authors led by Xiang Nan N indicates, the future of agriculture may very well lie in the tiny, yet potent, molecular dynamics within the cells of our crops. With such concerted efforts in research and technology transfer, humanity can look forward to reaping the benefits of healthier, more resilient food crops in the years to come.
Aroca R, Tognoni F, Irigoyen JJ, Sánchez-Díaz M, Pardossi A (2001) Different root low temperature response of two maize genotypes differing in chilling sensitivity. Plant Physiol and Bioch 39:1067–1073. https://doi.org/10.1016/S0981-9428(01)01335-3 10.1016/S0981-9428(01)01335-3
Battal P, Erez ME, Turker M, Berber I (2008) Molecular and physiological changes in maize (Zea mays) induced by exogenous NAA, ABA and MeJa during cold stress. Ann Bot Fenn 45:173–185. https://doi.org/10.5735/085.045.0302 10.5735/085.045.0302
Cao DD, Hu J, Zhu SJ, Hu WM, Knapp A (2010) Relationship between changes in endogenous polyamines and seed quality during development of sh2 sweet corn (Zea mays L.) seed. Sci Hortic 123:301–307. https://doi.org/10.1016/j.scienta.2009.10.006 10.1016/j.scienta.2009.10.006
Cazzaniga S, Li Z, Niyogi KK, Bassi R, Dall’Osto L, (2012) The Arabidopsis szl1 mutant reveals a critical role of β-carotene in photosystem i photoprotection. Plant Physiol 159:1745–1758. https://doi.org/10.1104/pp.112.201137 10.1104/pp.112.201137 23029671 3425210
Cervantes-Paz B, Victoria-Campos CI, Ornelas-Paz JdJ (2016) Absorption of carotenoids and mechanisms involved in their health-related properties. In: Stange C (ed) Carotenoids in nature: biosynthesis, regulation and function. Springer International Publishing, Cham, pp 415–454. https://doi.org/10.1007/978-3-319-39126-7_16 10.1007/978-3-319-39126-7_16
Christou A, Manganaris GA, Fotopoulos V (2014) Systemic mitigation of salt stress by hydrogen peroxide and sodium nitroprusside in strawberry plants via transcriptional regulation of enzymatic and non-enzymatic antioxidants. Environ Exp Bot 107:46–54. https://doi.org/10.1016/j.envexpbot.2014.05.009 10.1016/j.envexpbot.2014.05.009
Ding D, Li J, Xie J, Li N, Bakpa EP, Han K, Yang Y, Wang C (2022) Exogenous zeaxanthin alleviates low temperature combined with low light induced photosynthesis inhibition and oxidative stress in pepper (Capsicum annuum L.) plants. Curr Issues Mol Biol 44:2453–2471. https://doi.org/10.3390/cimb44060168 10.3390/cimb44060168 35735609 9221838
Du H, Wang N, Cui F, Li X, Xiao J, Xiong L (2010) Characterization of the β-carotene hydroxylase gene DSM2 conferring drought and oxidative stress resistance by increasing xanthophylls and abscisic acid synthesis in rice. Plant Physiol 154:1304–1318. https://doi.org/10.1104/pp.110.163741 10.1104/pp.110.163741 20852032 2971608
Feng Q, Yang S, Wang YJ, Lu L, Sun MT, He CX, Wang J, Li YS, Yu XC, Li QY, Yan Y (2021) Physiological and molecular mechanisms of ABA and CaCl 2 regulating chilling tolerance of cucumber seedlings. Plants-Basel 10:2746. https://doi.org/10.3390/plants10122746 10.3390/plants10122746 34961219 8705041
Fernández-Marín B, Roach T, Verhoeven A, García-Plazaola JI (2021) Shedding light on the dark side of xanthophyll cycles. New Phytol 230:1336–1344. https://doi.org/10.1111/nph.17191 10.1111/nph.17191 33452715