دانشگاه اصفهان علوم زیستی گیاهی 3041-9603 17 1 2025 05 22 Impact of Piriformospora indica on morphophysiological parameters of quinoa (Chenopodium quinoa Willd.) under salt stress تأثیر تلقیح قارچ Piriformospora indica بر شاخص‌های مرفوفیزیولوژیکی گیاه کینوا (.Chenopodium quinoa Willd) تحت تنش شوری 31 54 29870 10.22108/ijpb.2025.146299.1418 FA سعید ناروئی زاد گروه زیست‌شناسی، دانشکده علوم پایه، دانشگاه بوعلی سینا، همدان، ایران رویا کرمیان گروه زیست‌شناسی، دانشکده علوم پایه، دانشگاه بوعلی سینا، همدان، ایران Journal Article 2025 08 13 This study was conducted to investigate the effects of different salinity levels (0, 200, and 400 mM) and the symbiotic fungus Piriformospora indica on the growth and physiological responses of quinoa (Chenopodium quinoa Willd. cv. Giza1) as a factorial design within a completely randomized design (CRD) with three replications. The results showed that salinity significantly reduced plant height, plant fresh weight, panicle weight, as well as root length and weight. Additionally, salinity decreased the content of chlorophyll a, b, total chlorophyll, and carotenoids. On the other hand, salt stress induced a significant increase in hydrogen peroxide (H2O2) and malondialdehyde (MDA) (as an indicator of oxidative damage) levels, and secondary metabolites such as total phenols, total flavonoids, and total anthocyanins. The inoculation of quinoa with P. indica mitigated the adverse effects of salinity, leading to a significant improvement in all studied growth parameters. At the 400 mM salinity level, P. indica increased chlorophyll a, b, and total chlorophyll contents by 29%, 124%, and 58%, respectively. Furthermore, P. indica reduced carotenoid content by 16%, MDA by 7%, and H2O2 by 27% under the same salinity level. Moreover, inoculation with P. indica further enhanced the levels of antioxidant compounds, increasing total phenols by 18%, flavonoids by 16%, and total anthocyanins by 12% at a 400 mM salinity level. The findings demonstrate that P. indica can improve growth performance and alleviate oxidative stress, suggesting its potential as an effective biological strategy to enhance salt tolerance in quinoa cultivation. Introduction Water scarcity and soil salinity have a negative impact on plant growth, crop yield, and global food security, particularly in arid regions. Nearly 8% of global land and over 30% of irrigated areas are significantly affected by salinity. Intensive agriculture and poor water management exacerbate soil salinization, a problem expected to worsen with climate change. Sustainable solutions, such as cultivating salt-tolerant crops like quinoa (Chenopodium quinoa Willd.), are crucial for maintaining productivity in areas affected by salinity. Quinoa was domesticated approximately 7,000 years ago in the Andes. It is highly nutritious,rich in minerals (calcium, magnesium, phosphorus, iron, zinc), vitamins (B1, B9, C, E), oil (linoleate, linolenate, and natural antioxidants), and proteins with essential amino acids (lysine, methionine). The FAO recognizes quinoa as a climate-resilient crop, and it is now cultivated in over 50 countries, including the U.S., India, and Egypt. However, introducing quinoa into Iran’s saline agriculture requires understanding its salt-tolerance mechanisms. Salinity stress disrupts photosynthesis, nutrient uptake, and enzyme activity, inducing oxidative damage through the production of reactive oxygen species. Plants combat salinity through osmotic regulation (accumulating proline and glycine betaine) and antioxidant systems (e.g., catalase and superoxide dismutase). Endophytic fungi, such as Piriformospora indica, enhance plant stress tolerance by improving nutrient uptake, photosynthesis, and antioxidant activity. This fungus regulates stress-responsive hormones (e.g., salicylic acid and gibberellin), boosts chlorophyll content, and activates defense genes. This study investigates P. indica’s effects on quinoa (cv. Giza1) under salinity stress, assessing growth and physiological (photosynthetic pigments, malondialdehyde, phenolic compounds, and hydrogen peroxide contents) responses. Findings may advance sustainable strategies for quinoa cultivation in saline soils. Material and Methods This study investigated the effects of salinity stress and Piriformospora indica inoculation on quinoa plant (Chenopodium quinoa cv. Giza1) through a pot experiment conducted in a research greenhouse at Bu-Ali Sina University. The factorial experiment employed a completely randomized design with three salinity levels (0, 200, and 400 mM NaCl) and two fungal treatments (inoculated and non-inoculated), replicated three times in sandy-loam soil (pH 7.47, 0.72% organic carbon). P. indica was cultured on PDA medium (containing potato extract, dextrose, and agar) at 25 °C for one week, then transferred to liquid medium for 20 days to produce chlamydospore suspensions mixed with sterile sand for inoculation. Quinoa seeds were surface-sterilized using ethanol (70%) and sodium hypochlorite (1%), then soaked in the fungal suspension for 3 h before planting. Ten seeds were sown per pot at a depth of 1.5 cm, and the seedlings were thinned to three at the four-leaf stage. Salinity treatments were applied gradually at the three-leaf stage in three increments at 15-day intervals, with soil EC monitored after each application. Growth parameters (plant height, root length, fresh weights of plant, panicle, and root) were measured using rulers and digital scales. Physiological analyses included photosynthetic pigments (chlorophyll a, b, total chlorophyll, and carotenoids) measured spectrophotometrically using Lichtenthaler's method with acetone extraction, oxidative stress markers (MDA via TBA assay and H₂O₂ using TCA method), and antioxidant compounds (total phenols by Folin-Ciocalteu, flavonoids by AlCl3, and anthocyanins with methanol-HCl). All biochemical analyses were conducted using standardized protocols with proper controls and spectrophotometric measurements at specific wavelengths. The comprehensive experimental design and rigorous measurement protocols ensured reliable evaluation of P. indica's potential to enhance quinoa's salinity tolerance through physiological and biochemical modifications. Statistical analysis was performed using SAS software (version 9.4) with Duncan's multiple range test (P ≤ 0.05) for mean comparisons, and results were graphically presented using Excel. Results and Discussion The study demonstrated that salinity stress (200-400 mM NaCl) significantly impaired quinoa growth and physiological parameters, resulting in reduced plant height (55-66%), biomass (10-34%), and panicle weight (12-22%). These reductions likely are resulted from osmotic stress, ion toxicity, and oxidative damage, which are consistent with findings in other crops. Notably, P. indica inoculation effectively mitigated these effects, enhancing growth parameters (14-50% height increase, 18-28% biomass improvement) even under severe salinity. The fungus notably improved root morphology (22-30% increases in length/weight), suggesting enhanced nutrient/water acquisition as a critical adaptation mechanism reported in other halophytes. Salinity-induced chlorophyll degradation (20-36% reduction) and carotenoid loss (6%) were substantially reversed by P. indica (16-58% pigment increases), indicating its protective effects. This aligns with studies showing that fungal-mediated preservation of the photosynthetic apparatus occurs. The 27-77% MDA and 37-254% H2O2 increases under salinity confirmed membrane damage by lipid peroxidation, while P. indiaca causes antioxidantive system activation (9-27% oxidative marker reductions), paralleled by findings in soybean. Remarkably, the fungus increased phenolic (18-23%), flavonoid (16-30%), and anthocyanin (12-17%) levels beyond those induced by salinity, thereby enhancing its ROS scavenging capacity. This dual effect - both alleviating damage and strengthening defense - mirrors reports in mint (Khalvandi et al., 2019) and aligns with known fungal modulation of antioxidant pathways. The results collectively suggest P. indica's potential as a biofertilizer for saline agriculture, though molecular studies should further elucidate its gene regulatory mechanisms. Future research could optimize inoculation protocols and explore synergies with other stress-mitigation strategies for field applications. Conclusion The study demonstrated that salinity stress significantly reduced quinoa growth, as well as physiological and biochemical parameters, including plant height, biomass, root length, and photosynthetic pigments, while increasing oxidative stress markers (H₂O₂ and MDA). However, Piriformospora indica inoculation effectively mitigated these effects by enhancing nutrient uptake, chlorophyll/carotenoid content, and antioxidant activity (increased total phenols, flavonoids, anthocyanins). The findings highlight P. indica's potential as a biological agent to improve quinoa's salt tolerance in arid/semi-arid agriculture. Future research should investigate the molecular mechanisms underlying this symbiosis and the associated gene expression under salt stress. برای بررسی تأثیر همزیستی قارچ اندوفیت Piriformospora indica بر بعضی از ویژگیهای رشد و فیزیولوژیکی گیاه کینوا رقم Giza1 تحت شرایط تنش شوری (0، 200 و 400 میلی‌مولار نمک NaCl)، آزمایشی به صورت فاکتوریل و در قالب طرح کامل تصادفی در سه تکرار انجام شد. نتایج نشان داد که تنش شوری به صورت معنی‌داری سبب کاهش ارتفاع و وزن تر بوته، وزن خوشه، طول و وزن ریشه شد. همچنین، تنش شوری موجب کاهش محتوای کلروفیلهای a، b، کل و کاروتنوئید شد. از سوی دیگر، تنش شوری افزایش قابلتوجهی را در سطوح پراکسید هیدروژن، مالون‌دی‌آلدئید و محتوای برخی ترکیبات ثانویه مانند فنل، فلاونوئید و آنتوسیانین کل ایجاد کرد. تلقیح قارچP. indica اثرات منفی شوری را تعدیل نموده و منجر به بهبود معنی‌دار تمام شاخصهای رشدی مورد پژوهش شد. این قارچ در سطح شوری 400 میلی‌مولار، محتوای کلروفیلهای a، b و کل را به ترتیب 29، 124 و 58 درصد افزایش داد، لیکن موجب کاهش 16 درصدی محتوای کاروتنوئید، 7 درصدی مالون‌دی‌آلدئید و 27 درصدی پراکسید هیدروژن در این سطح از شوری شد. علاوه بر این، تلقیح این قارچ سبب افزایش محتوای ترکیبات فنلی شد، به ‌طوری ‌که محتوای فنل کل به میزان 18 درصد، فلاونوئید کل به میزان 16 درصد و آنتوسیانین کل به میزان 12 درصد در سطح 400 میلی‌مولار شوری افزایش یافت. در مجموع یافته‌های این پژوهش نشان دادند P. indica به علّت بهبود وضعیت رشدی و کاهش تنش اکسیداتیو، می‌تواند به عنوان یک راهکار زیستی مؤثر جهت افزایش تحمل شوری در گیاه کینوا مورد استفاده قرار گیرد.

https://ijpb.ui.ac.ir/article_29870_e5fd7b89365c7292364218cc1f628a5d.pdf